Image copyright Caroline Thurston Image caption Caroline lives on the water in Oxford

My Money is a new series looking at how people spend their money - and the sometimes tough decisions they have to make. Here Caroline Thurston from Oxford records her spending over a week and shares tips for saving.

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Caroline is 33 and works in higher education. She lives on a narrowboat, which she bought three years ago with an unsecured personal loan, which she repays at £705.42 per month. The boat is moored on a permanent residential mooring, for which Caroline pays £257.44 per month in mooring and boat licence fees.

In her spare time, when she's not doing "boat jobs" she runs a Guides unit in her village, and enjoys cooking Greek food. Over to Caroline.

Caroline's week: A nervous wait for an MOT result, and a comforting mug of hot chocolate

It's a grey, drizzly day, and the fire went out overnight. In the winter I tread a fine line between keeping the boat at a comfortable temperature, and inadvertently draining the batteries by running the heating pump continuously. A gravity-fed heating system which doesn't use an electric-powered pump would be more efficient but the upfront cost is beyond my budget at the moment.

People assume that living on a boat is cheaper than living in a house, but it's not - you just spend your money in a different way. Ask a boater what "boat" stands for and they'll tell you 'bring out another thousand'. And then they'll laugh, and probably weep a bit too.

Oxford is a cycling city (true according to sheer numbers, arguably untrue based on the lack of cycling infrastructure). I cycle to work every day so my commute is free.

I'm nearly out of contact lens solution, so I re-order three months' supply online (£17.00) through Amazon Smile, which ensures a donation goes to the RSPCA. I also re-order three months' worth of contact lenses (£35.77).

The weather is so grim that I cycle straight home and batten down the hatches. My solar panel hasn't generated much power today, so I run the generator for a few hours to boost the batteries. I need more efficient solar panels, as they will significantly offset my expenditure on petrol for the generator, and diesel for the boat engine (around £8 per week in total), but my current top priority is ordering coal for the winter.

Usually I buy enough for a month at a time, but this winter there will be a stoppage (canal closure) at a bridge just north of my mooring, meaning that Dusty the fuel boat will be unable to get through for three months. Ordering three months' worth of fuel in advance is a pricey business, and will set me back around £400-500 on top of my usual monthly bills. So, no new solar panels just yet.

Total spend: £52.77

Morale is low at work today, so I buy hot chocolates for me and a colleague (£3.40). After work I drop my car off at the garage for its MOT and say a silent prayer. The car is a 2003 Vauxhall Corsa which I bought two years ago from a colleague of my stepmother's and paid for in instalments.

Owning a car is probably as close as I get to "a luxury", but it improves my life immeasurably. It helps me stay connected to friends and family, and has brought down my food costs significantly, by enabling me to do my food shopping at the big out-of-city supermarkets.

I spend around £30 a week on food. I plan my meals, and always take my own lunch to work. I lived and worked in Greece for a few years, so I love cooking Greek food. A lot of Greek cuisine is inherently cheap (and tasty!). I make this lentil dish regularly, which is based on a type of lentil soup (fakēs).

Image copyright Caroline Thurston

On Tuesday nights I run a Guides unit in my village. I was really pleased to see that Girlguiding included financial literacy as part of the "skills for my future" theme, running across all ages in their revamped programme, which launched a year ago. Tonight though we have a rather soggy and chaotic game of Capture the Flag on the village green.

Total spend: £3.40

D-day. Will my car make it through the MOT? The mechanic calls me mid-morning with the welcome news that, aside from a pair of new tyres and a recommended oil-and-filter change, the car is fine. I pay £296.85, transferring money out of my (very tiny) savings pot. I will put the money back in at the end of the month once I'm paid.

Today I also receive a notification that my monthly Geocaching (an outdoor treasure-hunting game) subscription has been paid (£4.63). On the way home I stop at the post office to return my high-viz cycling jacket to the supplier, as the zip has broken. It's under warranty so the repair or replacement is free, but the postage costs me £8.70.

Total spend: £310.18

I have a meeting with a colleague today, but as all the meeting rooms in the building are booked we go to the university cafe next door and I buy the coffees (£3.30), which I'll claim back as work-related expenditure. Our office doesn't operate a petty cash system, so all expenses have to be incurred personally and then claimed back, which I think assumes too much about the financial situations of its employees.

Two years ago I acquired a £4,000 overdraft debt overnight (due to the Canal and River Trust omitting the VAT on my mooring fees and threatening me with a CCJ [county court judgement] unless I paid the VAT bill in full immediately) and I have been in the debt trap ever since. I recently consolidated my bank loan and overdraft, and my credit rating plummeted as a result.

Image copyright Caroline Thurston Image caption She bought her narrowboat three years ago

I have been using my credit card for the last year or so with great diligence in an attempt to improve my credit score. I never put more on it than I know I can afford, and I always clear the balance at the end of every month. Nonetheless, the interest rate went up when my credit rating went down, which is incredibly disheartening.

The poverty premium is very real, and can affect anyone, no matter how "middle-class" they may seem. Debt - and its impact on a person's mental health - is still a taboo subject. During the six-month process of consolidating my debts, I was very grateful for the support of a good friend who advises the Money and Mental Health Policy Institute. I am now part of MMHPI's research community, offering "lived experience" expertise and input to their work.

Total spend: £3.30

Dusty the fuel boat will be out for delivery next week, so I place an order via text for 15 bags of coal, two bags of kindling, and a bottle of gas, which in total will set me back £231.

My fuel costs are - unsurprisingly - weighted heavily towards the winter months, and every year I tell myself I'll set aside money during the summer. But I never seem to have enough disposable income to do it.

In the winter I burn around 50-60kg (£25-£30 worth) of smokeless fuel a week. A bottle of gas (£33) will last three months. I burn wood for heating too - it's useful to raise the temperature of the boat quickly, but it's not possible to keep the stove going overnight using just wood. Keeping warm isn't just a consideration of comfort - it also prevents damp and condensation, which would otherwise damage the fabric of the boat.

My neighbour has invited me for dinner this evening. On the way I stop at Sainsbury's to buy food shopping for next week (£34.34, including wine and chocolate for my hosts tonight and tomorrow) and to fill the car with petrol (£32.02, including a five-litre jerrycan for my generator).

Total spend: £66.36

I'm off to London to see my best friend. We haven't seen each other in five months, so we have a lot to catch up on! I would usually get the train to London, but there are engineering works this weekend and I don't fancy a three-hour schlep from Oxford to Upton Park, so I drive. In the afternoon we go for a long walk along the Greenway footpath in east London, then catch the bus back to her home (£1.50).

Total spend: £1.50

I am greeted on my arrival back in Oxford by a large pile of firewood outside my boat. In a bid to economise, five of us have pitched in for delivery of a tonne of wood, which my amazing neighbours have - in my absence - already distributed to all the boats. My share costs £14, but I also promise to buy the log-movers a drink at next month's boaters' drinks at our local pub.

Image copyright Caroline Thurston Image caption Caroline's tomato harvest

I spend the afternoon dutifully carrying out my weekly "boat jobs" - filling the water tank, stacking the log store, emptying the toilet, sweeping out the stove, pumping out the engine bay, and tightening the stern gland. Oh the glamour of it all! I also harvest the last of my tomatoes and peas, grown by our community-run gardening project in raised beds on the towpath, and make tomato and basil soup for dinner.

Total spend: £14

How does Caroline feel about her week?

With the exception of my MOT, it was a pretty typical week - there were no great surprises! It's encouraging to see that, as I suspected, my outgoings are on the essentials I need to stay warm, dry and fed. Unless I get rid of my car, I can't see how I'd pare back this week's spending.

I think I am a long way off from having sufficient disposable income to build up any substantial savings. Maybe some better solar panels are in reach, though!

Total weekly spend: £451.51