How much would it cost to replace 1 rear caliper ?

Part and labor cost around $150.00 to $200.00 For Cheap Car Only. High end car are more higher price are that answer your Question.

It all depends on what car your working on. But yes you can replace one caliper. Talk to steve or Paul.

Autozone only sells parts. If you're looking for labor, you need to talk to a local mechanic. You will need to call the store for specific pricing, but calipers typically run in the 30-100 range

Depends upon which one you need. You'll have to go online or to the store.