I usually hate the merchandise and shops in theme parks and avoid them like the plague but DLP is completely different! I LOVE the shops there and, yes, there are lots of them! Pretty much all of the buildings along Main Street are shops and there are two or three shops in each land plus small carts here and there. The shops are all themed to their land/ride etc and while there is a lot of crossover in the merchandise on sale you can also find more specific things in certain shops, etc swords, pirate hats etc in the shop next to Pirates of the Caribbean. As you walk around them take your time to take in all the little details. My favourite is the shop next to the Snow White ride - it has the dwarves cottage built inside it! Oh, and don't forget the Christmas shop in the castle!
Some things are expensive, dressing up outfits in particular, but generally speaking I think it's pretty reasonable (12ish euros for a soft toy, 7ish euros for a pin). I also think it's good quality stuff too. The t-shirt we bought for DD two years ago has washed really well and all of the soft toys are wearing well too.