shroom are easy and quick to propagate so they are pretty much the cheapest coral you'll find. if there's anyone in your area should be pretty easy to get some. Especially if there's a saltwater club in your area. but 5 bucks would be a pretty standard price for a single shroom at least the size of a half dollar for standard solid colors, probably more for striped, polka dotted or multicolored. and anywhere from 10 to 50 bucks for Hairys, Rics and Yumas depending on color and rarity, growth rates play a part in prices, obviously things that grow super quick there are more of so lower prices, yumas that take 6 months between splitting cost more. It's all supply and demand.