FoamTiles.com has a 25% off sale running through Tuesday, plus free FedEx econo shipping and no sales tax if you're outside Arizona.
They have 5/8" thick tiles in 12 colors to coordinate with your fursuit, or if you want something sturdier, the 7/8" tiles feel like they could stop a bullet (but only two color options with those). Each is 2 feet square, so one tile should be ample for a pair of sandals depending on your shape & size.
I got one each of the two tile types described above (5/8" in purple and 7/8" black/gray) to experiment with, total was $12.61 delivered.
They have 5/8" thick tiles in 12 colors to coordinate with your fursuit, or if you want something sturdier, the 7/8" tiles feel like they could stop a bullet (but only two color options with those). Each is 2 feet square, so one tile should be ample for a pair of sandals depending on your shape & size.
I got one each of the two tile types described above (5/8" in purple and 7/8" black/gray) to experiment with, total was $12.61 delivered.