Health-tech start-up GoodRx is in talks to be acquired for at least $1.5 billion, but could fetch as high as $3 billion, according several people familiar.

Health distribution giant McKesson was among the companies taking a look, one person said, but will probably not be the buyer. The identity of the other potential buyers could not be learned. No transaction is imminent and the talks may not result in a deal.

GoodRx offers people without health insurance, or with high-deductible plans, a way to shop for drugs at lower prices. The company makes its money when consumers use its drug discount cards at pharmacies. It does that through its relationships with the top pharmacy chains and pharmacy benefits managers.

GoodRx and McKesson did not immediately return requests for comment.

GoodRx isn’t the typical highly funded Silicon Valley start-up. It has only raised a small seed round of $1.5 million in venture capital from technology investors, including Founders Fund.

But in the fall of 2015, private equity firms Francisco and Spectrum made a growth investment in the company for undisclosed terms. Sources tell CNBC the company’s valuation at that time was more than $300 million.

The company is attracting a lot of attention from buyers due to its impressive growth in recent years.

It is on track to generate $100 million in earnings this year before certain expenses (EBITDA), one of the people said, making it one of the most successful companies in the burgeoning health-tech market.

The founders of the company — Doug Hirsch, Scott Marlette and Trevor Bezdek — hail from technology companies like Facebook and Yahoo. They started the company with a mission to help people find the best deal on their medicines, knowing that prices can vary widely depending on the pharmacy.

Industry experts say that GoodRx is a quiet success that demonstrates how a real business can be built that is targeted to low income Americans, and not just the rich.

“They serve consumers who are under-insured or un-insured and with increasing costs, do a great service towards filling the gap,” said Tahla Sattar, founder and CEO of Nimble Pharmacy, who has closely watched the company’s rise.

“GoodRx is a great example of how to do well by doing good,” he said.