anythign mail order will cost more then buying locally, that is if you have reasonable prices at the LFS. Shipping IS what costs so much.
I was going to order some fish from a LFS in calgary and have them shipped up but jsut the shipping was going to be 60$.
The people in my club that ordered fish from armkes shipping was only about 2$ per fish but they ordered hundreds of dollars of fish.
All in all it will most likely be cheaper to buy locally.
If you want cheap check out the clubs inyour area. Since joining mine i have hardly paid for fish. Or the auctions are also great, I got tons of fish for 2$ each that sell for 20$+ at the LFS.