It seems that being a communist Anti-American homosexual superhero (according to Fox News commentators) pays.
Action Comics #900, the standard edition, has hit $31 on eBay.
This may have been a fluke, most copies are selling from between $15 and $25. Either way, the sell out of first prints and the continuing publicity is bearing fruit for speculators.
Strangely, the rarer incentive variant covers aren't going for more money. A set of all three covers only fetched $52. It may well be that the standard cover's appearance on TV screens means that's the copy people want.