i'm in the same boat... but the truth is this... if you can afford internet, you can afford good food... it's a choice...
no offense, and please don't think i'm hating on you... b/c hey, i'm making the same choice, clearly...
i pay like $150 a month for cable and internet but i say that i can't afford doctor's appointments

ha
it's all about choices...
when it comes to diet, it will take some journaling on your part to figure out how you are triggered by certain foods...
some will definitely make you feel better... some worse... for whatever reason, things w/cottonseed oil in them can cause me to flare up in a weird way... don't know why... but it's true...
also, the stomach ibs stuff gets worse w/raw foods... waay worse... so as much as i love peppers/onions, i can't eat them unless they are cooked to death!!!
same w/some raw fruit...
i'd say just shop sales...clearance sale red tagged bananas have the same nutritional value as bright new bananas... just a little mushy...
i went through periods in grad school where i lived off of bread and peanut butter for weeks at a time... so i'm still struggling w/the concept that food isn't a luxary... it's a necessity... but i'm getting better w/time...
like the wise animated creatures in over the hedge say... humans tend to live to eat instead of eat to live...
i wish i had an appetite, that's probably why i rambled so long about food... ha

good luck and hope it works out... also, try coupons.com see if that helps...