the question is what quality of a paint job do you want? by the sounds of it you want what my paint supplier calls an "afar" paint job. it means it looks good from afar but up close you know a pro didn't do it. so to answer the title roughly 1/2 pint of paint will do it. but to do it right you are talking about 100-150 in materials assuming you don't have the cleaners, sand paper and will find a gun to borrow. and keep in mind the fender wont match the rest of the car exactly the right way to do it would be to blend the new paint into the surrounding panels. as for skill level i am a parts guy and paint all my own stuff i have never taken a course but i do a decent job. get friendly with one of your parts stores that supply paint and ask away. it seems over whelming at first but you tube can help take some stress out and remember you can always sand paint off if you don't like how it came out.