I was recently going through a couple boxes in one of my closets and came across a price guide from 1999 published by Non Sport Update (Roxanne Toser fame). Wow! That's all I can say. The following sets and prices are for MINT condition cards (appear to be new) according to the guide:
1967 Die cut set 1-44 (minus Ratz/Cracked) $275
1969 Wacky Ad Series w/o #25 $150
1973 1st series white backed set $200
14th series set $85
15th $95
16th $100
Wow... I will buy anyone's MINT sets (do they even exist?) at those prices all day long! She lists some of the middle sets pretty close to what they may go for today in say EX condition, but definitely not in MINT. I have to be honest though, I don't remember those sets going for anything near that low back then...