5 yen discount?

ご縁市
I saw this sign posted on a self service gasoline station(where I come from is called petrol station). It literally to say 5 yen discount ( go en ichi?) but the words does not mean that. Can anyone here explain true meaning behind it?Thanks.

ご縁市 is not "5-yen" or "discount." Note that if it was "5-yen," it would be 五円 or 5円.

This term is often used to refer to small markets (市) held by local farmers or local shops, or just to refer to sales at some supermarkets, and includes the word 縁 ("en"), encounters or fate bringing people together. This "go" is for polite expression, not for number five :)

So maybe at the gas station they had some small scale sales going on, and wanted to advertise it in a friendly way :)