There is no direct link between exercise and seroma resolution. Sounds like the aspirations were effective the skin flap scarred into place and the potential space is now closed.
Free tummy tucks do not exist but Care Credit and Altheon may allow you to finance the surgery. It may also be wise to call your nearest plastic surgery residency training program to see if there is a clinic that can provide your surgery at low cost.
A tummy tuck performed by an experienced board certified plastic surgeon who understands your goals will look natural when done correctly. It’s a good idea to check out before and after photos available on surgeon websites to see if their aesthetic matches yours.