Is it new or used? Does the seller have good or bad feedback? I have gotten a couple items of Ebay and overall it was very good, but it all depends on the seller.
Another risk is whether the Avia keepcase still contains the original 3 video calibration filters in blue, red and green. (These can be obtained after the fact, but at the price of hassle/time).
For everyday user calibration (Contrast/Brightness/Tint-Hue/Sharpness/Color controls) one can just as well get the Sound&Vision Home Theatre Tune-Up disk (made by the Avia people) for $16 online; it uses one blue filter. It can be found at amazon.com barnes&noble.com and elsewhere online.
I hated S&V. It took too long to get to the test patterns. I like the menu system on Avia much better and with all 3 filters, I can calibrate my tv even better. With only one filter, I was calibrating to one color and the other colors would be off. With Avia I can get them all perfect but I can get to a happy medium where all the colors are close.
As far as ordering off ebay, I do it all the time. As long as the disc isn't scratched and it contains all 3 filters, I'd do it. I ended up getting mine from amazon for about $36 I beleive. A worthy investment.
Mash the menu button on the remote during the opening music of AVIA and you go straight to a menu from which you can select "advanced AVIA"--this takes you straight to the audio/video tests.