What can I donate to get a free tummy tuck?

Frankly, it is unlikely that you will find a plastic surgeon who will be able to do pro bono work for you; there are a lot of expenses associated with performing these procedures, besides that of the surgeon's fees. Also, frankly speaking, it does not sound like it would be wise for you to proceed (see below) with elective plastic surgery.Generally speaking, the “ideal” patient for tummy tuck surgery is one who has completed pregnancies, is psycho socially/emotionally/financially stable, has an excellent social support system surrounding him/her, is capable of arranging enough recovery time, does not smoke and who has reached a long-term stable weight. Remember, that every operation carries risk of complications; the occurrence of a complication may also carry additional expenses. I hope this helps. Best wishes.

The idea to donate, maybe the skin of the abdomen, is admirable. But the area is not big enough to process that small amount of skin cost effectively. As you might imagine, if there was away to get abdominoplasties for free, it would be in widespread use already!