Diy paint/high school budget

Easy to get carried away here. As I understand your wants & needs you are on a tight budget and thats cool. I would not use anything but something specific for auto work. The price of all this stuff is going space schuttle upward. If I want budget automotive stuff, I like the Martin Senour product. Cost effective, should be available locally (our dealer was NAPA with a trained guy) and will do everything you want. Just be aware of the law of diminishing returns. Once you start sanding for primer, you will not know where to stop. Then it will be well I will fix this, then you will want to fix that and it never effen ends.
But, that is not an inherently bad thing.
My $00.02 worth---Good luck, we are rooting for you.
DR------:coffee2: