I used Quikcrete Play Sand for my cichlid tank. The only concern is the fine powdery white stuff that gets in the water column. Easy fix: Dump some in a 5gal bucket (quarter full), add water, stir it up, dump out the now white water, repeat till water doesn't turn white anymore.
Another concern: hydrogen sulfide gas buildup in the sand if you spread it too thick. To make double sure I don't have hydrogen sulfide slowly poisoning my fish, I just stir up the sand in the tank about once a month to release any big bubbles that have built up.
Play sand is about $4-5 for 50lb.