NOTeveryone agreed with the RAC when it said that petrol could become cheaper than bottled water.

RAC wagered that if the price of oil slid below $29.15 barrel, it could push petrol prices to $1.87 a litre - while a fall to $14.58 a barrel or less could see petrol sold at 86c a litre, or cheaper than a bottle of water.

So at $30/Barrel - WTI is now over 60 times cheaper than a bottle of sparkling water. Perrier (per Barrel) $1850 — David Ingles (@DavidInglesTV) January 12, 2016

But only if you are a water snob, according to the Hydration Council, who emailed us to say that the average price of a litre bottle of water, purchased in a multi-pack, is 79c. Take that, Perrier drinkers.

The oil price has continued to slide after the lifting of economic sanctions against Iran. The newly liberated country is expected to pump fresh reserves of oil into an already oversupplied market, making oil even cheaper.

On Monday, the price of a barrel of Brent Crude dropped below $28 and Twitter started fighting over things that are more expensive than a barrel of oil, including a barrel.

A barrel of WTI crude is 3 times cheaper than a steel drum to put it in. pic.twitter.com/1mSqx51SlS — Patrick DeHaan (@GasBuddyGuy) January 14, 2016

They ranged from the proverbial:

The way the oil price is going, by the end of this year it will be cheaper to buy a barrel of oil than a sack of maize. — S01E01 (@GomoLeb) January 12, 2016

To the relatable:

Two large pizzas - cheaper than a barrel of oil. #도미노피자 — Ol' Brandon (@BrandonLockhart) January 13, 2016

To, inevitably, booze. A native Londoner writes:

It's surely only a matter of time before a barrel of crude oil will be cheaper to buy than a pint in a London pub. — Derek Murray #2331 (@DerekJMurray) January 13, 2016 Barrel of oil is genuinely gonna be cheaper than a night out in Nottingham — Ray J Verma (@rayverma_) August 24, 2015

The Canadians chipped in to boast about their cheap beer:

A barrel of oil is now cheaper than a two four of beer in British Columbia. via r/Showerthoughts https://t.co/SnE44jKuKW — shower thoughts (@showerthotbot) January 17, 2016

But more expensive doesn't always mean better, as Ian White revealed:

WTI Crude now trading at $29.59 US a barrel, now cheaper than a pair of pants at @Target. #cdnpoli #oilprice pic.twitter.com/AC7nywuMPK — CTV - Ian White (@CTVIanWhite) January 15, 2016

He might be advised to stick to the barrel of oil.

Falling oil prices probably won't do much to the price of pizza and beer, sadly. But it might benefit drivers - just as long as savings get passed on at the pump.

RAC said that there was scope for retailers to cut prices by another 10c on the average price of diesel.

"We are concerned that too few drivers are benefitting from these incredibly low oil prices as many less competitive retailers are still selling fuel at far nearer to $2.28 a litre than $2.08," said Simon Williams, RAC spokesman.