The trees behind the car should look familiar; they were used for "Collector's Gallery."
One thing you can do is buy the Playboys from 1974 to January 1985 and you will end up with every Nagel that appeared.
That tends to be more cost effective than buying pages.
I think I got my whole cache for maybe $70 total.
1974 has images in April, July, August, and full page Ballantine's ads in November.
1975 has images in January (mmmike's avatar), and then August through Dec.
Therafter there is an image in every issue, though the December 1976 stuff barely looks like Nagel and seems very cartoony to me.