I just buy live and do cervical dislocation to them. No chance of getting bit and still fresh. As for price, I pay $8 for large live rats and $3 for small live rats. $4 for an adult mouse is way too much. Are you buying from a pet shop that sells their mice as pets? Those tend to be more expensive vs buying from a reptile shop or some pet shops that have 'feeders' which are usually just the white mice and not the 'fancy' mice. I think the mice from where I buy my rats from are $1.50 or something close to that. I don't feed mice so never really paid too much attention. It's also a reptile shop where the owner has her own rat and mice colonies going.