The Blazer was one of the vehicles I seriously considered when looking for a "new" used vehicle in 2005-6. The pages upon pages of complaints about blown transfer cases, differentials, ball joints, and warped rotors just turned me off. I understand, cheap is cheap. I've been there myself, working on my own cars to keep them going. But you know, there comes a point when a person wants to live like a real human being, and not have to spend their time nursing some junker along. That has always been Chevy's selling point --- at least it's cheap. That is enough for some people, but I don't think it's too much to expect something more than that. If something needs to be fixed every other week, whether it's by a mechanic or by you, it's telling you something about the quality of that vehicle.
The kid here is right. Learn to do some of the work yourself and save a lot of money! For example...
>>"Car would just decide not to start. Turned out to be a faulty distributor cap plus rewire and replace plugs $793.62."<<
A cap, wires, and plugs from an auto parts store costs at most $100 and takes maybe 40 minutes tops to install. I just saved you almost $700!
>>"Needed to completely replace the brakes $805."<<
I just replaced recently all the pads and two rotors on one of my own vehicles, and the parts cost all of $150. I just saved you another $655.
>>"Replaced the rear differential (housing and all) and a new battery $1491.60."<<
Now this one has me really curious. Why was the differential housing replaced? If it was damaged then this isn't a maintenance issue. As far as replacing it goes, you can get a good used one for under $250. I'm also curious why you'd have a battery replaced when this work was done. But given that you likely had all this work done by a dealer, I'll allow $150 for that. So on this I saved you $1,091.60 for a total savings of $2,585.60 in three jobs that are pretty easy to do.