1998 Isuzu Trooper - Loud Grinding/Spinning Metal noise

My 1998 Isuzu Trooper with 99,000 miles recently started making a loud metal on metal noise. It sounds like a someting spinning. It does not get louder or softer by acceleraton, but start loud and quiets a bit after a few seconds. Then as I drive a few minutes the noise seems to get louder.

I took it to a local repair shop hoping for the best and semi prepared for more. Much to my surprise they were able to find many things wrong.

Here is what I was told is wrong. The cause of the noise is the Air Conditioning compressor and all that comes with that. They said that since Isuzu runs on 1 belt, it is important to repair. Cost $1389.00 w/labor. Then the water pump. Has a small leak. 680 w/labor. Then the rear calipars are locked (news to me) $1100.00 (pads rear and bac, which by the way both replaced in last 15 months). You see where I'm headed. 98 trooper - $3000 in repairs, I'm not sure it's worth it. The problem is I still owe a couple grand on the care and can't scrap it. I'm looking for advice. I plan on getting some sort of second opinion. Not so much because I don't believe them as much as I need a fix for cheaper! Any ideas?

J