Being born and raised down there I would suggest either Hollywood/Hallandale Beach or North Miami Beach for a cheaper place to stay and easy access to SoBe/the Grove/ Lauderdale and even Palm Beach.
As for food, it depend upon what you eat, how much you can fork out and where you are staying. Some of the best ethnic food in the country can be had in NMB, insane Cuban, Jamaican and Hatian foods and on the cheap too.
I personally stay north of Hollywood, you couldnt pay me to go down there anymore and I have family that I havent seen in a few years because of it, but you know what they say, different strokes for different folks