These tinfoil badges were given away free at garages when drivers purchased ESSO petrol back in 1970. The DFC badge was just one of a series of Scottish & English crests in the collection, and there was also a gatefold folder that went with them to keep the full set in.
This particular round "red crest" was used on Dundee's strip from 1970 to 73. I remember you could also buy a cloth version of this badge from sports shops which you peeled the back off of and stuck onto the replica shirt. However, after a few washes the badge lost it's stick and fell off, so they usually just ended up on scarves and school bags.