Posted By:
Rich Klein Are in pre-1973 sets with those scarce series. One of the 1974 Topps Checklists -- I believe #273 used to show up on just about every want list of 74's I saw and in addition, 1979 Topps Al Fitzmorris #643 was a bear for me to find in 1979 to finish my set. And if you check; for some bizarre reason, that card is still very low on the PSA Pop report. It took me forever and a day to get the 1962 Topps Bill Skowron green tint card.
In the 1980's; back in my dealing days; and especially if from my past history; I either had a good supply of that card or knew it was not that expensive; I gave away many cards to those people who just needed one card to finish their set. That was usually for cards of $1 and under.
Don't ask the people who wanted the tough 66 and 67 Hi # Mets or 71 Topps Al Weis or the 61T Bill Skowron if I gave those cards away 
Edited because when I posted in another thread; I realized what I wanted to add here and realized I had put the wrong year. All is good now
Regards
Rich