Where can I get data on different food item prices for the various fast food chains?

Question

I want to do an econometrics project on the variation of prices between different chains in different cities. For example, I want to know the price of a McDonald's single hamburger, double hamburger, fish fillet sandwich, etc. in different states. Then I want to know Burger King's prices, then Wendy's, etc.

Answer 1

http://fsrin.com/login.action (foodservice research institute) has a menu mine, but you have to have a membership.  im not sure how much it is.  they have thousands of chains.