I'm afraid I've bad news for you. Although from a later year this set belongs to the “communal jetons” (gemeentepenningen). These started at the end of 1979/beginning of 1980. At first these were cheap (25 BEF) but when they saw their was a market for they got greedy and the issue price raised, 50 BEF, 100 BEF and like yours 150 BEF. So at a certain moment this market collapsed completely and nobody wants them anymore. Nowadays you can sometimes find them as kiloware on auctions. I'll see if I can find some of those back.
Here's a set of mine (actually two, one in bronze, one silver plated, I've made a picture of one side of each) comparable with yours:

Look at the stamp at the reverse, it's the same issuer as your set:
