It's the same price for frozen or live where I get them from. I was a little surprised and thought that a live animal should be more expensive than a dead/frozen one, even if just a little bit, but then I wonder if maybe it's because of the cost of keeping the frozen ones frozen is higher than it is to keep them alive in tanks.
Plus, when people go and buy a live rodent, there's a good chance it will be kept as a pet. And if it's a first pet, there's a good chance those same people will also purchase an enclosure, bedding, a water bottle or bowl, food, etc., etc., etc.! So they are most likely making more money off of the live rodents as it is, and don't need to charge a higher price.