I have no idea what coin it is, but I figured I'd give ancient collectors a bit of a heads up. There's a possible coin that was holed and turned into a charm on a necklace: http://www.shopgoodwill.com/auctions/Stunning-18K-Italian-Snake-Chain--Coin-Pendant-15563108.html It could also be a faked/aged token, but even if it is fake, the 18k (4.6g) chain is real.
Yeah, It's a Late Roman Bronze. In that condition you would find it in the $5 bin at a coin show or coin shop.
4.6 gm 18k gold chain (per the picture of the chain on a scale) = ~$147 in gold at the current spot price. Value of the coin is negligible. If you're looking for an 18k gold snake chain at a reasonable price, you will be hard pressed to find one a similar one under ~$250-300+ (1mm 18" snake chain). If you're looking at it for melt value, the price is already too high.
Depends on the goal. Selling at a 'cash for gold' place? Lose. For gold investment? Maybe, if there are no further bids. For wearing as a nice 18k gold snake chain? Win.
Assuming the price stays there, it's okay, but the price on that site tends to jump in the last 8 hours. Not like eBay sniping, but similar. Also, the bale on the coin is 18k, which isn't included in the 4.6g... might add another .08-.15 g.