I agree with pontiacgp 60 gallon is just about right.
The less it runs the better while painting because of the inline vapour moisture it creates from hot compressed air as it cools down.
Oil less compressors don't last long because they don't have a lot of CFM an will run alot/endlessly to supply enough air to spray paint.
You can get cheap inline air filters from a paint store or go on the high end an buy water separator an a high micro dirt filter.
2 stage compressor an 80 gallon is really nice, but cost, but will last for years.
It's all about funds an how well you want your paint job to turn out.
I'll edit an add this in, as for paint guns, lve seen cars paint with cheap guns (HF) that turn out amazing an some that turn out farmyard bad. Alot will have to do with prep work an type of paint your blowing on. Get yourself a good respiratory.
If your in this hobby long term everything you buy is an investment an yes it's resalable.
I'm not even sure anymore how many guns l have 7-8-9? from $100 to $800 ea. I have 4 13-14mm tip that are back-ups just cause sh*t happens. When your spray high end paint $500cad plus you don't want to get caught un-prepared.
No l wouldn't say l'm a painter but l have been painting 1 or 2 cars each year for 30 years. So you do collect stuff over the years.