There are lots of different recipes, but the one that looks cheapest and easiest to make is this:
50% alumina hydrate and 50% kiln wash.
Alumina Hydrate seems pretty cheap. 1 lb 2.09
Kiln Wash is pretty common as well. – 1 lb 5.15
Plus some water to a pancake batter or thick soup consistancy. Approx 3 – 3 1/2 lb bead release = 7.25
Bead Release = about 4 oz starting at 5 bucks.