Bought one today at Academy Sports in Pensacola. HOWEVER, all I got was a receipt from FWC and the actual stamp is supposed to be mailed to me. Florida is supposed to be participating in the e-stamp which allows you to buy it online at myfwc.com. I'd try there.
I got my online last year. They send you a receipt that serves as your stamp until the real one is sent to you. Got mine in plenty of time to hunt. Will purchase online again this year.