There’s Eric Martin of York, Pa., for example. He’s about to become an “Accidental Millionaire” through the deal, reports Bloomberg.

Martin, who is the founder of a startup called IdeaDash, won Jet.com’s nationwide marketing competition—Jet Insider—in early 2015. The contest offered a reward of 100,000 shares of Jet stock to the contestant who got the most people to sign up for 6-month free trial “insider” memberships to the membership shopping site, a sort of online Costco or Sam’s Club. According to his company’s website, Martin took first place out of the 350,000 people who participated, getting over 8,000 people to sign up.

Walmart Is Buying Jet.com for About $3.3 Billion

Martin spent $18,000 on online ads, Bloomberg reports, and now has a stake in Jet that is reportedly worth millions. Although Martin told Bloomberg that he is not sure exactly what his stake is worth, Fusion reported in February 2015 that his piece could be valued between $10 million and $20 million.

And considering the money the company raised in the months since the contest (at growing valuations)—not to mention the premium Walmart paid—his stake could be significantly higher today.

“It feels good; it feels really good,” Martin told Bloomberg. “The way I think to describe it is ‘occasional hysterical laughing.”’

Martin’s windfall comes courtesy of Walmart’s desperate need to better compete with online retailers like Amazon.com (AMZN). Walmart (WMT) reported its slowest online business sales in a year during the latest quarter, while online sales at Walmart were $13.7 billion in 2015, according to research firm Internet Retailer. The Jet.com buy has Walmart shelling out $3 billion in cash as well as $30o million in company shares.

Is a $3 Billion Sale a Failure?

Walmart and Jet will work together to develop new offerings, while remaining distinct from one another.

Fortune has reached out to Martin and will update the story if he responds.