They might be free, but in Oklahoma City, Thunder playoff shirts allow fans to wear their hearts on their sleeves.

Scan the crowd at the Chesapeake Energy Arena, and nearly all 18,203 fans will be wearing the T-shirt provided on their seat, some topping the designer suit or $50 Thunder shirt they wore underneath. It's not like that in every NBA market.

The Thunder will hit a milestone for Wednesday night's game against the Memphis Grizzlies: The 500,000th playoff shirt will have been given away to fans. That's half a million free shirts since 2010, when the team first made the playoffs.

Die-hard Thunder fans have amassed stacks of T-shirts from the team's four runs in the NBA Playoffs; Edmond teen Jackson Kinnear has even tried collected them all (he's lacking just one.)