The sweet shop sells chocolate frogs - they are $9.95 plus tax and also those revolting jelly beans for the same price, lots of other things too. You can buy wands, outfits, scarves, key rings - the usual stuff really.
We went in november and the queues were horrendous, my SiL made us queue to get in the sweetshop, it was ridiculous - and then we got to Orlando airport to fly home and they had loads of things in the US shops in there!!