Depends if you buy new foam. If you buy all new gymnastics foam, about 1000-2000 for the foam, and maybe 500 for the other stuff needed. But you could always go around to mattress shops and get old foam, or apholstry stores, or foam stores if you have one around and ask for old foam
just have to find foam! It was actually really easy to get the foam. we just called a bunch of gymnastics places and found one that was replacing the foam in their foam pit, so we went and picked the old foam up.