NEW YORK (CBSNewYork) — Sneakers today are much more than athletic footwear.

For 25-year-old Sam Sheffer, footwear is part fashion, part financial investment. In the past decade, he has spent thousands of dollars on his sneaker collection, saying it’s a safer bet than the stock market.

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“There’s not one pair of sneakers that I bought that has gone down in value,” Sheffer said. “There are some shoes I spent $200 on that I can get $800 for.”

The sneaker market is surging. Just last year, the U.S. sneaker industry grew 8 percent to $17 billion and the resale market is estimated at over $1 billion a year alone.

The craze is so big, there are even specialty stores that sell limited and hard-to-find sneakers.

Sue Boyle, owner of Rime in New York City, says the sneaker culture started in the 80s when Nike teamed up with Michael Jordan on the Air Jordan line.

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Now sneakers are high fashion.

“Now you’re seeing women starting to wear it,” Boyle said.

Like the Fenty shoe, a collaboration between Puma and singer Rihanna. Boyle said they sold out in three hours.

Apps like Kickster let users know when the hottest sneakers are coming out, Sneakmart lets users buy, sell and trade sneakers on the secondary market.

Sneakers are so popular, there are even conventions dedicated to the product taking place across the country.

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The Cradle of Aviation in Garden City will host Laced Up – The Long Island Sneaker Convention on July 30. For more information, click here.