During the 1960s the Shell Oil company undertook major advertising campaigns that involved nice-looking, patriotic tokens or medals. They were awarded to anyone who filled up their car with gasoline. The collecting instinct in many of us (me included) returned to the gas station to gather as many prizes as we could. It was a good advertising campaign.
Today these medals are still around and they are still collected. The US President Medals were popular. The Prime Minister medals covered Canada. Other advertisers followed suit, and coin collecting received a boost in interest as well.
Values of these medals today is very low and strongly dependent on condition. Poor examples sell for a few US cents. A single uncirculated medal can fetch upwards of $1 US dollar, sometimes $2 or more. A complete set of uncirculated specimens can bring near $50 if an interested collector can be located.