Looks Greek, not sure about the denomination, looks similar to 2 Greek coins I have from the similar time period that are copper-nickel but can't be 100% on the attribution.
It is Greek 50 lepta, Paul 1. Thankfully, you have a 1957. That is the key date for the series. Post a pic of the back, and I may be able to grade it.
Stats:
Date Mintage F VF XF UNC BU
1957 5,108,000 1.00 5.00 40.00 210 450
(I'm sorry for the bad organization of the table, the numbers are in order of condition.)
Every one knows it isn't unc, but maybe it is an XF (it should be probably at least a VF, but it is really the back that wears down).
That is why you should pay attention to foreign non-silver, too. If someone was given a common-date walker or this coin in UNC, most would choose the walker, but the value is greater in the CuNi coin this time.
Nice drachma, I agree on the value sagittarius gives, I've seen it go for about a buck in fine condition and yours is better than that so maybe up to $5. very unique find!