Once you get your diet figured out (and to me the definition of "clean" is the least refined version of a food that is available) I have some ideas for you on budgeting:

o Obviously use your diner connections with wholesale suppliers. maybe you can order some foods that the diner doesn't usually stock, like egg whites, cottage cheese, etc.
o Don't get "gamed" when shopping. a sale price at an expensive store may be worse than the regular price at another store. Learn the stores in your area and their prices. Keep a file in your phone or PDA of the foods you buy a lot of, the typical price at several stores, and the best price. then you can decide what to buy, where, and when rather than being fooled into "good deals". this is the best thing i've ever done for shopping (if needed calculate the price per oz or ml so you can compare different sizes)
o sign up for online sales fliers if available, get the little points key fobs but never buy something just because it gives you 300 points or whatever. redeem your points (which you earn by buying only the lowest price items) on money off your purchase, never appliances or whatever, which will be massively overpriced.
o buy dented or short-dated foods where possible
o buy in bulk, like bulk bins or order huge bags of oats, rice, etc.
o save money on supps by getting them vetted on this forum before buying overpriced, crappy BBing brands