If you are going to buy tamales in Mcallen you have to go to Delia's. They have 2 restaurants in town and I prefer the restaurant on South 23rd st. They have red salsa there and the other usually has green.
You cannot beat their cream cheese and jalepeno tamales. You can purchase a zillion different types of tamales by the half dozen or dozen. Also, if you want you can purchase them frozen which can be convenient since most of their restaurants are a little out of the way.
A must for tamales!