Can trade for IGB.
Any good items your have in animal crossing to sell.
If you breed a lot of hybrids can make a hybrid shop and sell 2btb a hybrid.
If you can draw, maybe doing quick, cheap doodles for ppl!
All I can think of right now ; ^;
Posting, selling items or in game bells from Animal Crossing are your only ways that I can think of. Or selling game codes or Pokemon. Maybe selling art and collectables too.
Don't stress out about it! It's really kind of you to do a giveaway but I'm sure everybody would rather you give yourself a break than handle it anyway
If you wanted to, I would suggest putting a 'looking for donations' blurb in the thread title so people who have a lot will know to donate there.