I say it is better to feed frozen thawed, not only because you will be saving money but because you can easily store it and do not have to worry about the mouse bitten your snake(a dead mouse wont bite back!), Also the freezing process kills any parasites the mouse may have been carrying while live!

Look at Rodentpro.com they have great prices on all size rats and mice along with other whole prey items.

http://rodentpro.com/