Depends on who's bidding this week. Some of the deep pocket eBay bidders seem to be on vacation lately, but it will definitely get up there. I would be very surprised if it went for under $500. Like nymark said, this one doesn't come around very often.
Funny thing though, sometimes when something fetches a high price, suddenly a lot more copies come out of the woodwork.
As a seller though, listing a rare item after another has sold for big bucks can work against you. If too many come onto the market the price drops. And there's always the possibility that the one buyer who will put up the big bucks for the item now has it, and yours will go unsold. Anyway, yeah, good for us if more copies surface, for sure.
Aftermath is an interesting piece to read, but I don't think it's very good. Same with 20 Tanks... They are obviously the work of a young writer. To me, anyway. But what do I know. Your mileage may vary. I realize that anyone who buys this isn't buying it just to read the story. Now something like the lost issue of Write --- that could be a buy-it-just-to-read-it situation, in addition to its value as a rarity.
It's all academic to me anyway, I can't afford this shit. ;)