In the latest example of corporate greed in the pharmaceutical world, the US state of West Virginia announced today that it's investigating the makers of the EpiPen for Medicaid fraud - which means they think it's defrauded the US government healthcare system.

More specifically, it's accusing manufacturers Mylan of inflating the price of EpiPens by almost 500 percent since they purchased the life-saving device back in 2007.

Since then, the cost of a single EpiPen has gone from around US$57 to $318 - a 461 percent increase. Which is pretty frustrating when you consider that many people with allergies need to keep the medication on them at all times in case of going into life-threatening anaphylaxis. Anaphylaxis can be triggered by anything from a bee sting to eating trace amounts of peanut.

In the face of the public backlash over their price rises, at the end of last month, Mylan announced they'd be releasing a generic version of the EpiPen that would cost only $150 per injection.

But industry insiders were quick to criticise this apparent act of goodwill, with pharmaceutical experts telling NBC News earlier this month that they estimated an EpiPen would only cost around $30 to make.

Now a bio-hacking collective called Four Thieves Vinegar has tested that claim out for themselves, and shown you really can engineer your own DIY EpiPen - which they called the "EpiPencil" - for around $35. And they claim it works as well as the $300 version - although we definitely don't recommend you try it at home.

The main difference between their version and the one you can buy at the pharmacy is that you have to measure out the correct dose of epinephrine before using the DIY version.

"We've gotten many requests to do something about the EpiPen, so we have," says Michael Laufer, one of the founders of Four Thieves Vinegar, who has a PhD in mathematics from the City University of New York.

"We developed the EpiPencil, which is an epinephrine auto-injector built entirely from off-the-shelf parts, which can be assembled in a matter of minutes for just over $30."

EpiPens are designed as 'last resort' devices that are filled with epinephrine, an adrenaline drug that's more than 100 years old. The drug itself isn't patented, but what makes the EpiPen so attractive is the fact that its design lets pretty much anyone use it - which is handy in emergency situations.

So why haven't many other companies stepped up as competition and made an EpiPen equivalent to rival Mylan's? As Jamie Condliffe explains for MIT Technology Review, a big issue is the patent problem.

Mylan has the patent on the auto-injecting device up until 2025, and while it would be possible to build another type of model that does the same thing, it makes things a lot tricker.

"[There's] fear of creating a device that doesn’t work reliably, and a regulatory process that makes getting products to market incredibly difficult," writes Condliffe.

Four Thieves Vinegar has now published a video and fully downloadable instructions on how to make your own DIY EpiPencil at home.

To be clear, we're definitely not recommending you go out and make your own EpiPen. The Four Thieves Vinegar version is not only totally unregulated, but it also hasn't been shown to reliably work for everyone - something that would require years of clinical trials and peer-reviewed papers.

"It's essential to remember that epinephrine auto-injectors are life-saving products, and it is critical that they are made to a high standard of quality so patients can rely on them to work safely and effectively," said US Food and Drug Administration spokesperson, Theresa Eisenman.

But as an experiment to show that the EpiPen really can be created for around $30 - and with non-bulk parts at that - the Four Thieves Vinegar DIY version definitely makes its point. And hopefully it reminds people that they shouldn't have to pay ridiculous amounts for life-saving medicine.

"You know there are people who are just not buying an EpiPen because they can’t afford it," Laufer told The Parallax. "That’s unconscionable."

With West Virginia's new investigation and the public still pretty pissed off about the cost of EpiPens, it'll be interesting to see what happens next. Your move, Mylan.