The best things in life aren't free. They cost 30 Pizza Points plus $3.99 shipping and handling. Everything from toys to cigarettes had proof of purchase points, and if you could manage to not lose them, they bought some pretty awesome stuff.
The trend started with Kenner's offers on Star Wars toys in the '70s:
Source: whovianscreate.com
Source: dallasvintagetoys.com
In the '80s, "Pizza Points" could be found on the back of Teenage Mutant Ninja Turtle toys:
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They were redeemable for prizes like this inexplicable life vest:
Source: terrible2z