A lot of people don't realize the amount of time it takes to paint a car the 'right' way.
Considering the amount of time it would take to sand the entire car, then spray the entire car with paint that is more expensive than regular house paint for probably around 3galloms for our car (I'm just ball parking), and then another layer of clear coat.
If they're serious they'll tape off all the details, remove trim, possibly remove the bumpers. So on top of the supplies cost, they've got labor charges, and then if they're a good shop you have to pay them for that too.
However the shop that quoted a minimum of 4000 I wouldn't go with, if they didn't see the car and what work that needs to be done then is it really a quote?
Then also the cost of whatever it would normally be for that same company to remove the dings, how many, so on.
You could attempt to spray your car yourself, and it would be cheaper, but maybe you should get a quote on the paint, sand paper, plastic rolls to lime your garage maybe, painters mask and kit, and whatever else I'm not thinking about.
As far as the dings, id let a pro do them.
And those cheap MAACO jobs will look tacky (not tacky as In the style but it'll almost pop in color), this is because of the lack of a clear coat and if no real prep work is performed then the bonding surface won't be as good and can result in bubbles pretty easily. On top of that the paint job will look good from 5 feet away for a couple of years, after that it'll start to look like poo again, sometimes they last as long as 5 years from what I've seen.
Anyways, if you think you've got some of the know how and the ambition to your entire car I suggest watching some videos and reading a lot of how tosh before buying anything to know what you're dealing with.