Einy hasn't cost me much yet, being a young dwarf, o. mercatoris. He seems happy eating every other night. In two and a half months he has cost me about $30, and I could have saved most of that had I ordered online from the get-go.
He has eaten about a dozen hermits and exactly ten fiddlers in the time I've had him.
At www.keyscritters.com you can order blue leg hermits, 100 for $26 plus shipping. He likes the small hermits better because they are easier to conquer than a fiddler crab, but at www.aquaculturestore.com you can order fiddlers ten for $13.95 shipping included. I like to switch it up.