Let's imagine that you are a film buff, like me, and one of your favorite films is Night at the Museum, an enjoyable romp and nice showcase both for the special effects and the actors, notably Ben Stiller. A good film, and you're no doubt excited about the sequel, Escape from the Smithsonian that's in production as I type this!

You really like this film. I mean, you really like it, you've seen it upwards of thirty times and you decide it'd be very cool to get a Night at the Museum poster like they would have displayed at the movie theater when they were screening the film (in the biz we call these "one sheets"). But where to go?

Ah, eBay! Of course! A quick search on the site for "night at the museum poster" reveals that there's one auction, only one, that's running and that it's for an "original movie poster".

The bummer is that there are two days left and the current high bid is almost $25, plus $10 shipping. Kinda steep, really, for an older film that wasn't a blockbuster. Nonetheless, you want it and you don't really want to research other ways to buy one that might not involve an auction, so you bid $30.

And your bid is the high bid. For now.

A few hours later, you get an email from eBay saying that someone else has outbid you and that the poster is now $31. So you dutifully go back to eBay and bid $50, because you really, really want that poster. You're the high bidder at $45 (which means that the other bidder had a high bid of $44, of course).

Ninety minutes before the auction ends, you get another of those cursed eBay messages and, in a burst of eBay auction fever, you bid $75 and decide to just camp out on that page, reloading and reloading until the auction closes.

You win, with a closing bid of $71 (plus $10 shipping) and are psyched.

But was it a good deal? Heck no.

Dig around a bit on the eBay Stores and you'll find that you could have just bought the very same poster from a fixed-price merchant for $20 or less, with only $5 shipping. Ouch. Worse, if you were to simply have gone to Google and searched for buy "night at the museum" movie poster one sheet you would find over 2000 matches, all less expensive than your $81 poster that you've yet to receive from the auction seller.

My general advice is to spend 10-15 minutes before you place a bid at an auction ascertaining the general going price for the product. Then you'll know, and you can bid accordingly (or skip bidding entirely and just buy it: I have not infrequently seen items on eBay where their starting bid is higher than the same product for full retail elsewhere online)

That's the size of things. Be careful out there. :-)