They may be common, but don't call them junk. These are pretty interesting coins and it's that elitist (It must be gold or silver or its junk) attitude that scares new collectors off. This is NOT the place to be bougie.
The bulk of my collection is world circulation pieces like Mexican 20 Centavos which were minted from 1943 to 1972 (The Reverse changed a couple of times slightly).
Yes its a common coin worth around 50 cents, but it is VF and most of these 1940s and 1950s ones are VG or worse, so its a decent piece.
And those asking if its silver, Numista is your friend.
Loving Halfcrowns. British and Commonwealth coins 1750 - 1950 and anything Kiwi.
If it's round, shiny and silvery I will love it.