Skinny-dipping in the Shore Club pool at 4 a.m. Crashing Star Island parties. Smuggling lipgloss through MIA security. Looks like someone’s idea of a cheap thrill could use an upgrade. What could be better than finding a 70 percent-off Valentino? You can get the same print — and someone to create a handmade knockoff — for less than a ten-spot per yard at Rex Fabrics. At the little-known gem, spools of high-end designer fabrics go for as little as $4.99 per yard and furniture upholsteries for a little more. (Balenciaga couch cover, anyone?) After you buy, hit up one of the store’s much-in-demand seamstresses, who will make you a dress for about $80. It’s a hot way to get your kicks. And far more dignified than doing donuts in the 7-Eleven parking lot. Rex Fabrics, 825 Southwest 37th Avenue (305-448-7651 or rexfabrics.com).