A coworker of mine inherited a large collection of US proof sets and mint sets from the 1970's to 2000's. She is interested in selling them to me. The ones I've seen are in perfect condition. What is a fair price to offer her for each set? I believe that the PCGS or Coin Values published prices are inflated. I want to be fair to her, since she has no idea what they are worth, but I don't want to overpay for them either.
A good place to start might be the Redbook prices. If you pay about 75%-80% of Redbook, I would think that would be fair. Someone else might have a better suggestion.
