What size F/T?
I've had to buy from the big box pet stores in a pinch. Lg adult mice are around $3.50 each if you buy a 4 pack or about $4 each for singles.
I also had to buy a 6 pack of fuzzies and I think they were about $11-12 if I remember correctly.

I would try to take Freakie_frog's advice and buy bulk from a reptile convention. I just bought 50 lg adult mice for $30. So I got 50 for the price of of about 8 at the pet stores.

I am in the process of trying to find a good online supplier too, but the conventions seem to be the most economical way to go.