We ate at Gaido's in Galveston about four or five years ago and it was probably the best fresh seafood I've ever eaten. There weren't prices on the menu if I remember correctly because they go off of current market price for seafood. It's right by the beach, if you like that sort of thing. There's also La King's candy store downtown if you have a sweet tooth. It's like going back in time in there. They have all kinds of goodies.
The Fisherman's Inn in Port Isabel used to be good, but I haven't eaten there in probably 30 years. Port Isabel is on the mainland across the causeway from South Padre.