It's been one of the most controversial pieces of medical equipment in recent years - the lifesaving Epipen, which has become so expensive, its manufacturer has been accused of inflating its price by almost 500 percent since 2007.

But now, after nearly 150,000 people signed a petition asking for a lower-cost alternative to the Epipen, America's largest pharmacy, CVS, has announced that a cheaper, generic alternative will be on shelves from today.

"We're encouraged to see national efforts to make epinephrine auto-injectors more affordable and more available to Americans across the country," said Cary Sennett, president and CEO of the Asthma and Allergy Foundation of America. 

"Partnerships that increase access to vital medications are key in helping those suffering from life-threatening allergies."

For a bit of background into the impossible situation Epipen users have found themselves in recent years, since pharmaceutical company Mylan bought the rights to the Epipen back in 2007, the product has undergone several substantial price-hikes.

As we reported back in September, since its acquisition in 2007, the cost of a single EpiPen has gone from around US$57 to as much as $318 - a 461 percent increase. 

That's a whole lot of money to charge someone who has no choice but to pay, because the Epipen is designed to protect people with serious allergies from going into life-threatening anaphylaxis. 

Anaphylaxis can be triggered by anything from a bee sting to eating trace amounts of peanut, and those with serious allergies need to keep an Epipen on them at all times in case they're unexpectedly exposed to an allergen.

And EpiPen injection contains a small amount of the chemical epinephrine, which narrows the blood vessels and opens airways in the lungs to treat symptoms such as severe low blood pressure, wheezing, itching, and hives that can be fatal if not addressed immediately.

After the intense backlash Mylan experienced from the public late last year, when the state of West Virginia announced that it was investigating the company for defrauding the US healthcare system due to repeated price increases, the company relented - a little.

"Mylan announced they'd be releasing a generic version of the EpiPen that would cost only $150 per injection," Fiona MacDonald reported for us at the time.

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

Now, Epipen users have a third option on the table.

According to a press statement from CVS, which has 9,600 pharmacies spread across the US, their version of the Epipen will cost $109.99 for a two-pack, so $55 each.

Called the Adrenaclick, the generic epinephrine auto-injector will have to be bought in twos, which means it's still a substantial cost for low-income users, and CVS does stand to benefit greatly from the product, both from sales and publicity. 

But it's plain good news for Epipen users that they now have a far cheaper alternative - and the fact that there's now some serious competition in the market might force the price down even further in the future.