I've had
good and bad experiences with SkyAuction in the 8 or 10 auctions I've won. Yes, you need to have
some flexibility (although I've often gotten the exact dates I wanted). But on the plus side, they've been more than willing to cancel three auctions where availability became a problem (take
that, priceline.com!).
As for prices, it's VERY hit or miss. I generally decide on a price I'm willing to pay, and autobid that (don't forget to factor in the tax & delivery add-on). This is easy since they tend to repeat the same offers weekly. Most of the time somebody will outbid me (even if it's crazy - $500 to Europe in the winter?!), but every so often the gods come through. For example, three weeks ago I got SFO-LHR for $608 total (summer travel). Same auction last week went for $900!
And some good news: SkyAuction tickets earn miles and are upgradable

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[This message has been edited by johna (edited 06-03-2000).]