Black Oranda...
I am Obsidian

not GoldfishGoddess

I know, I know... we have the same avatar.
Anyway the cost depends on the loach. I only know about dojos, and for them, the golds are more expensive than the spotted or peppered. At a LFS I got a gold for $13 and at Petsmart I got it for $10. The Peppered and Spotted usually run around $5-6.
They are great, some of my favorite fish. I think I heard them called the 'ferrets' of the fish world. Oh, and they make noise when they are out of the water. I got one from the LFS and I scooped him out and as I will putting him in he squeaked! I almost dropped the net.
Goodluck!
Oh and Banjo, if you want to see more pictures
http://www.loaches.com is a good place to look.