It depends on your style. Are you “budget friendly” or do you like extravagance, like fancy restaurants or lots of drinks? Does the hotel include breakfast? Do you eat $10 per person lunches or $40 per person lunches (which may include drinks)? Or would you settle for fast food, which may be even cheaper?
Sign up for restaurant websites and you will get coupons for discounts or free meals (if you are into chain restaurants).
I was just in Philly for Spring break with my 6 year old. We stayed near the airport at a hotel that included breakfast (Fairfield Inn and Suites, which is owned and operated by Marriott). It included breakfast, which saved us some bucks. For two of our meals, we ate at a chain across the street (Ruby Tuesdays) and we shared one meal as neither of us are big eaters. We ate lunch once at a place called the Reading Terminal Market, which is a whole bunch of stalls and with lots of spots to sit, under one roof. It was fun and there was huge variety.