Some are rare, some aren't. Are you looking for an identification of this coin? This looks like a bronze from Klazomenai, but it would be nice to see the reverse and size/weight. There is at least one relatively rare reverse with this obverse, although there is also a common or at least not-rare type too.
http://www.asiaminorcoins.com/gallery/thumbnails.php?album=124 http://www.wildwinds.com/coins/greece/ionia/klazomenai/t.html I watched this city, but this city I have not found it, and he can, but I have not found.
Now that you've shown the reverse it is much easier. Paschka, I am usually able to find coins very easily using CNG's archives. You may want to try that in the future for your unidentified coins. It will significantly decrease the number of coins you have to post here for identification help. For instance, now that you've shown the reverse, I went to CNG's archives and in the fourth box ("Search") typed in the terms AE, athena facing, nike. The resulting list was small and coins similar to yours were easily found. Example from that search result: 288, Lot: 260. Estimate $100. Sold for $75. This amount does not include the buyer’s fee. SELEUKID KINGS of SYRIA. Antiochos I Soter. 281-261 BC. Æ (15mm, 2.53 g, 2h). Smyrna or Sardes mint. Helmeted head of Athena facing / Nike advancing left, holding wreath and palm; monogram to outer left. SC 315a; HGC 9, 167. Good VF, dark grayish-green, almost black, patina, some fine cleaning scratches.
