In addition to others' great advice. You might want to look at mintages per year and see what grades like PCGS and NGC advise for selling prices of their graded coins. While that might not be completely helpful if you have an ungraded one, it can help with relative value compared to other coins of the same type, despite grades. For instance there are several instances where earlier coins in that series are quite valuable despite being well worn. Just a starting point...
Stay well,
Diy89Nurm7