THIS...IS...SPARTA!!!!

i'd say lift heavy, many sets, do HIT cardio, do heavy ab excercises, if budget is an issue, go to the grocery more often and just buy chicken that needs to be cooked in a day or so, it'll be discounted and give you the protein you'll need, brown rice is super cheap too, you'll also want to cut your calories so you can eat soup real cheap too and it's low in calorie same goes for oatmeal. Some fruits vegetables can be pretty cheap if you buy and cut them, also sweet potatos are filling and pretty cheap.

hanging leg raises will really develop your core too.