I am trying to determine fair market value for 6 sets of differents
Franklin Mint collections - history of mankind, history of american
west, opera's greatest moments, some yearbooks from 1970's , a couple
of others.

not as easy as i thought it would be. want to know if they have
collector's value or if they just get melted down.

Coin collecting is called numismatics.
However, even the American Numismatics Association (www.money.org)
doesn't want to answer your question.

If I were you, I'd go to this forum to ask your question of people who
collect coins. http://forums.collectors.com/  Don't be surprised if
they treat you a wee bit poorly, as they tend to be a bit snooty about
their hobby.

Good luck!