Definitely you can buy, u they keep until boarding the plane. You claim your bag with your receipt on your way to board.
We did buy some stuff.
Careful with the prices though....often cheaper in the malls.
A tip if you have a laptop with you. Do internet pricechecks if you have time and inclination.
At Orlando International in May, DH had his eye on an Archos electronic gadget. We whipped out the laptop sitting on a seat next to the Hyatt. Straight on the free wifi connection. Found several prices cheaper by buying over internet from home. So were able to make right judgement not to buy!