Paint and bodywork are 100% area dependent for cost. If there's more work than people to do the work in your area, the costs are high. If you're near a trade school that teaches bodywork, the costs will be low.
$300 won't even be enough to get someone to Talk with you where I live. Rust repair, assuming it's just bubbling under the paint and the metal is still solid enough it doesn't need to be removed and replaced, is easily $1000. And clearcoat coverage will probably be someone saying they won't do it unless they can shoot the whole vehicle, which would put you back another $2000~3000.
Prices are because there is a *LOT* of labor involved. Do some of the labor yourself and prices will come down some (talk to specific people to find out if they're willing, and how much). BTW, this is why people with limited money but a desire for nice stuff will buy the tools and learn to DIY. Paint work is not hard, the tools are a little expensive (but you could buy everything you need for the money you have), it's all labor and learned skill. You won't get perfect results the first time, but if you own everything to do the work you can keep trying till you get a result you like for minimal extra money.
