Check Reef Life, Fishes of Eden, etc... they always have them for around a buck a piece.
I have 1 turbo and 4 astreas in my tank. Doesn't look like they do much either... but the turbo is a monster. Get 2 turbos and like 5-10 astreas and your set. Hermits are good too, but some can be pesky... none of mine have picked off any of my snails yet. So that means there is plenty for them to eat. What you might want to do is slowly buy some of them so they don't stave to death.