i just bought a new truck (used) and the body is in awesome shape, but the frame has rust on it. i would like to stop the rust asap so it doesnt get worse because i plan on keeping this truck for a long time. so would it be best to leave it as-is, take it to a oil spray place and just let them go at it? or would it be better to scrape the rust off, paint it, THEN get it undercoated with the oil? i want to do the least amount of work because i simply dont have that much free time, and the little free time i do have i dont want to spend it working even more. also, any idea how much it would cost to take my truck to a paint shop and have them prep and coat the frame with a heavy duty rust paint?