Boop, this site has pretty good prices on their sale stuff: $2.75/yard & up:
https://www.fabricdepot.com/index.ph...e&pageid=15313
& this site has tons of awesome kids fabrics....some on sale @ $5.00/yard & up. But, maybe if you contact them & tell them what you are doing, they may be willing to drop prices even lower, or even donate to your cause. It might be worth a try:
http://bugfabric.com/bargain.htm
LOVE those hearts!