Sorry I don't know what your coin is, but I like it. You have, however, begun a journey that countless other collectors have taken; A journey for knowledge, history, and romance. Where else could you buy a ticket like that for only $6? Best of luck.

Nice pick up for the price! Can't tell by picture's. Hope somebody knows if not you  will have to look it up or bring it to a dealer. One that you trust. If no one has an idea then you'll have to send it in to one one the graders. Let's hope someone recognize it. Hope it's good. Congratulations. Mike

It appears to be a coin of Philip II, the father of Alexander the Great.  Your photograph of the edge looks odd, though, like the edge was smoothed out or filed smooth.  If it looks like this is so, a filed edge, then consider the coin carefully as to why this was done.  The little burn mark on the obverse makes it look someone zapped it using electrolysis.  The first sentence here, though, answers the question you asked.  If it weighs 4 to 6 grams or so, score.  These coins were heavier because the metal contained brass, I imagine, and were not just copper pieces.