I just thought I would add my comment here as I read all the comments here before I used these fastpasses. I bought them off ebay....10 of them, and as they only cost £30, I thought I would take the risk.
We went last week and the passes worked fine. The seller even let me pick them up form her house. She told me that the passes were the ones given out with the annual passes a few years. She also said she was ex-crew so picked up, quite literally, hundreds of these before leaving her job. So I suppose they are technically stolen items.
I don't know if they will be lifetime, or if they'll stop working within a year (as they are given out with annual passes). I don't even know if they'll work on a second visit as we only used them on the one day with a visit to both parks.
For approx. £3 a fastpass, I suppose it would be worth it, however, when we went, there weren't great queues anywhere in the park, so weren't really necessary. By the way, I bought the ones which showed the actual picture of the grey pass on ebay. I wouldn't buy the ones where there is no picture of the actual pass, and now, having bought them once, I suppose if I were to re-buy some, I would want a picture of the back as well. As I don't know if the ones I have will work on a second visit, I think I'll buy another set before we re-visit the parks (but only if we go at a busy time).
I read a comment by WDW crew regarding these on Yahoo, so added my experience there too, but my summary is: I wouldn't buy them if I were going at a quiet time....they are perhaps useful during holidays, however, at busy times, by midday, often, all the fastpass times have already been allocated for the whole day....so is it worth it? I hope these comments help......and no, I'm not related to the seller!