Want another opinion?
I would skip Nassarius because they don't seem to live long, and Trochus get big and would be obtrusive in a 10-gallon. I would also pass on Margarita snails because even though they are arguably one of the best algae eaters, they are temperate (not tropical) and when kept in a tropical tank they have a considerably shorter life span because of the increased metabolism. I would not add a starfish, shrimp, or a Conch or this tank as these would all starve in the long run in a 10-gallon.
I would suggest a couple Cerith Snails for the sandbed because they are the only true detrivores that are readily available, a couple Spiny Astraea (these are better than Pyramid Astraea imo), and later down the road add a couple Ring Cowries (they are a bit sensitive, so better to let your tank settle in first). In a couple months re-assess and add a snail or two if required. You won't need to spend $30, probably half that.
