There are many informational tools which track the changing price of gold coins on eBay, such as the Goldprice tool.
Of course, the price of gold coins everywhere rises as the spot price of gold rises, and since July the price has been up and down, but generally rising.
There is another factor which is pushing up the price of gold coins even more though. As the media coverage of the price of gold and its value as a 'safe haven' investment grows, people who would not normally consider gold at all are now being informed it is a smart move to get some gold, and are heading to eBay and the other auction sites in droves, to get their hands on some.
The effect of this is to make the bids at some gold bullion coin auctions go farcically high, as several naive bidders go against each other.
Attractive looking, but fairly ordinary coins are getting large prices for their sellers.
So what do serious, long term investor/collectors of bullion do? This is difficult to answer, but I'm not buying at the moment, until things calm down.