Are US Commemorative coins worth buying, especially if a seller may not know what he has and is selling like $50 under Red Book value? Or, is it better to spend my money on US Mint Silver Proof Sets? (Also: Is there a difference between a Mint Set and a Proof Set?)
A mint set contains uncirculated coins that have been taken from that mint’s regular production run. A proof set, IIRC, uses specially polished blanks that are struck on special presses in a limited run. A proof set is priced higher than a mint set, and should bring a higher price when you sell it.
I collected coins for many years, and when I went to sell them I couldn’t get anything more than the melt value, even for my uncirculated coins. IMHO, there are many reasons to collect coins, but as an investment is not one of them.