Dig box substrate mix?

[J4ckdaw-]

I happened to find Repti-Soil at pet smart says it's good for digging and burrowing wasn't sure if that would be safe to use. I was also looking for plain organic top soil and kids play sand some people say to mix the topsoil with play sand but was vague on the kind.

For the dig box for my old beardie, I used a mix of organic topsoil (no fertilizers, additives, manure, etc) that you can buy for $4 from Home Depot and play sand which was around the same price. It worked, and it was cheap. Idk, that’s just what I used