On my old beater truck the wheels were getting pretty rusty so I spent most of a day sanding them down with an orbital sander, getting them as clean as I could, then rattle can primed them using one of the one part etching Auto Primers, then top coated them. Now about 18 months later they're starting to get a little rusty again.... There's cheap, and there's value. You've gotten three pieces of very good advice about prep and finish.