Several places to check out are:

Cala Pardices - The best restuarant in Praiano! It is a 5 minute walk from La Perla hotel along the road and then you will see a sign post for Africanna nightclub, follow the steps down and you will see a sign for the restaurant.  Everything is homemade and fresh and you would find it hard to spend more than 45 Euros!

La Trattoria- Another nice place although the service is slow.  Also has fanstatic views of Positiano, next to the main catherdral.

La Brace - A nice restaurant, although it is mainly seafood.  

There are also several other restaurants in the main town centre of Praiano and also on the main beach.

Just outside Praiano (in direction Amalfi) there is an excellent restaurant called Le Pirate. They serve very good food at reasonable prices and the sea view is beautiful.