The Impetus
In developing some apps that had to support older devices, I had to acquire a previous generation iPod Touch for testing purposes. I figured a 3rd generation 8GB iPod Touch would be fine. So I set off to eBay to quickly grab an iPod.
After a few days, my new-to-me-but-used iPod Touch arrived in the mail. I took it out of the box and plugged it into the iMac, only to have XCode tell me I had a 2nd gen iPod Touch in my possession.
I checked my eBay order to make sure I hadn't ordered the wrong thing. Nope; 3rd gen 8GB iPod Touch. So I assumed the seller had sent me the wrong item. I contacted the seller, and was informed I'd received the correct item. I was ready to go off on the seller, but I first checked the Apple page on identifying iPod models. It turns out, we were both kind of right.
You see, technically, there is no such thing as a 3rd generation 8GB iPod Touch.
The Confusion
In 2009, Apple introduced the 3rd Gen iPod touches; they released new 32GB and 64GB models, but didn't release a new 8GB model. So for a time Apple sold the 2nd gen 8GB iPod Touch alongside the new 3rd gen 32 & 64GB models (Wikipedia reference).
So what had occurred, was that the seller had identified the 8GB iPod as 3rd generation, because it was sold alongside the actual 3rd generation iPod Touches. It's easy to see how this confusion might occur, but in looking at Apple's own page on "Identifying iPod Models" (source):
iPod touch (3rd generation) features a 3.5-inch (diagonal) widescreen multi-touch display and 32 GB or 64 GB flash drive......The iPod touch (3rd generation) can be distinguished from iPod touch (2nd generation) by looking at the back of the device. In the text below the engraving, look for the model number. iPod touch (2nd generation) is model A1288, and iPod touch (3rd generation) is model A1318.
it becomes clear that there is no such thing as an 8GB 3rd generation iPod Touch. And that Apple would refer to the model number of the 2nd generation iPod Touch in the blurb about the 3rd gen suggests that this confusion may be common.
Why Does This Matter?
If this were simply a matter of getting the wrong model, that would be one thing. But if you look at the pricing (as of the date of this post) of the 8GB 2nd gen vs. the 8GB 3rd gen, there's a big difference:
These are the exact same thing; iPod Touch model A1288. It would appear that sellers on eBay are profiting from this confusion; selling the mislabeled 2nd gen iPod Touch for a higher price than the correctly labeled 2nd gen 8GB iPod Touches. Whether this is intentional or not is difficult to say, but it is something you should be aware of if you're in the market for a used iPod Touch.
In my case the seller was friendly and willing to accept a refund, but not everyone might be so fortunate.
Bottom Line
If you're looking to buy a used 8GB 3rd generation iPod Touch (or any used iPod Touch, really), refer to Apple's page on "Identifying iPod Models" first to make sure you know what you're looking for, and don't end up paying more than you should.