Burning fat on stomach.. fast?!?

Hey so I am 5'4 about 120 lbs and I really need help :( I eat a good diet and I am not saying I am soo obese but I really wanna look good this summer!! so here is the long list of cants haha, I cant spend $$ to buy anything!! I cant drive anywhere, I cant go outside to job so basically I am stomache inside my house doing the sit ups, crunches etc.. So basically my questions are.. 1. What exercises can I do at home for free? 2. Will doing sit ups and crunches give me a flat stomache? How long itll take too.. sorry for all the work but thanks :)