I caught a mouse in my apartment and gave it to neighbor-friend who wanted a little pet. After about a year it developed a horrible skin problem. She took it to NYC's Animal Medical Center (major veterinary teaching and research hospital that has basically all the equipment and specialists that a human hospital has). I don't know how much she spent on it, but she took it there at least 3 times, and you don't get out of there for less $100 per visit at an absolute minimum (that's when they just look at the critter -- any treatment or medication is more). Mousie's condition was terminal, but with nightly baths in special medication, followed by some medication lotion, and some medicine added to its water, she kept it comfortable for several months.
You're really serious? I couldn't do that and it's not because of the money. It's the tail, too creepy. My outside cat will catch mice (we live with pastures & fields all around us) and I'll get the mouse from her and put it in a bucket. Then I wait for my husband to come home. It's up to him whether he kills it or lets it go - depends on how injured it is. But a mouse for a pet - like I said, couldn't do it.
Thanks for sharing - I feel better now that the heat's off of me.