I'm using 100 kilograms/220 pounds of what's essentially play sand in my tank without issues, the same sand is in another two smaller tanks, and a friend has 60 kilograms in his. It's probably worse than play sand, it has all sorts of bits of gravel and small rocks, and was full of twigs, gumnuts, bits of leaves, and loads of silt and clay that I rinsed out of it. It's probably more like 75 kilograms of sand after rinsing. 
It was also $4.50AU per 20kg/44 pound bag, hard to beat that price.
Water was noticeably a bit cloudy for the first month or so but got clearer with each water change. No issues with sand in filters or damaging impellers, even on the smaller tanks where the filter intakes run straight to the impeller.
Just rinse what you've got thoroughly, until the water's running relatively clear from the rinsing bucket. You'll get a bit of cloudyness in the tank, but it should pass.
Or, take it to the beach, build a castle, and buy some pool filter sand on the way home.
It was also $4.50AU per 20kg/44 pound bag, hard to beat that price.
Water was noticeably a bit cloudy for the first month or so but got clearer with each water change. No issues with sand in filters or damaging impellers, even on the smaller tanks where the filter intakes run straight to the impeller.
Just rinse what you've got thoroughly, until the water's running relatively clear from the rinsing bucket. You'll get a bit of cloudyness in the tank, but it should pass.
Or, take it to the beach, build a castle, and buy some pool filter sand on the way home.