Small businesses nationwide participating in this year's Amazon Prime Day on Tuesday grabbed a piece of the action on what turned out to be the top-selling day in Amazon's history, according to the company.

Sales for small businesses and entrepreneurs grew by more than 60 percent compared to last year's Prime Day, according to Amazon. A company spokesperson later told Inc. that "thousands" of small businesses participated but declined to provide a specific figure.

"Yesterday was phenomenal," says Lawrence Bibi, founder of Light Accents, a New York City light fixture manufacturing company that has participated in all three Prime Days so far. "I think it was even better than all of the days from last year, including Christmas and Black Friday and Cyber Monday. It was our strongest day in the last two years."

Bibi scheduled ad campaigns, sponsored products and lightning deals--where Amazon features specific products at heightened discounts for a few hours at a time--throughout the week, but ended up selling out his inventory before his first lightning deal could run. Even so, he says, sales were at least 25 percent higher than this past year's holiday season.

Something similar happened to Caron Proschan, founder and CEO of Simply Gum, who was participating in her first Prime Day. Simply Gum's lightning deal for 20 percent off all-natural chewing gum--the minimum discount required for Prime Day participation--began at 6 p.m. Monday night. It sold out in a couple hours. "That was surprising for us," she says. "We thought it would take at least an entire half day or day to sell out."

Simply Gum registered a 703 percent revenue lift compared to an average Monday night, says Proschan, adding that yesterday's sales (which included no lightning deals) earned the company 46 percent more revenue than an average Tuesday.

Proschan acknowledges that discounts cut into Simply Gum's profit margins, but says gains in brand awareness and customer acquisition--which won't show tangible impacts immediately--will be worth the relatively slim payout.

Laura and Michael Dweck, co-founders of Basic Outfitters (who were on Shark Tank in January), also reported approximately 50 percent higher sales than average, which matched the upper end of their expectations going into Prime Day. Basic Outfitters offered deals ranging from 25 to 50 percent off, which the Dwecks surprisingly say didn't cut into their profit margins--due to their ability to buy in bulk in preparation for Prime Day and the customer propensity for buying "you may also like" items.

Kristin Rae, founder and CEO of Normal, Illinois-based Inspire International, took a more hands-off approach. She says her preparation amounted to temporarily increasing her spending on Amazon sponsored products and social media marketing. Inspire International still posted double its average sales, which Rae says is great--even when compared to last year's Prime Day, when her company posted triple its average sales.

"I think everybody would love to sell a million units," Rae says. "It's kind of like winning the lottery. But I guess I'm more grounded in the reality that there's only so much traffic to go around."