Many folks know of the HTC Dream (aka T-Mobile G1) as the first Android phone available to the public, but Google actually had another device kicking around internally while developing Android. It never saw a public release, but you can buy one right now.
The Google Sooner is a prototype device made by HTC, and several of them have gone up for sale on eBay (via Android Police). They're priced at $195 each and are being sold by a seller named "drumsticks" who specializes in selling drum kits and accessories, but apparently dabbles in unreleased smartphones.
The seller has a feedback score of 4245, a 99.5% positive feedback, and are based in San Francisco.
These devices being sold are advertised as being new, but they've been sitting around for 10 years so it's unclear how many of them actually work. There's no paperwork or anything like that included, but you do get a battery, AC adapter, and earpiece.
Considering how old the Sooner is, its specs aren't going to be anything great. They include a 320x240 display, 1.3MP camera, TI OMAP 850 processor, 64MB of RAM, a 960mAh battery, and support for 2G wireless connectivity. So yeah, this thing is definitely going to be more of a collectible than something you'd actually use day-to-day.
That said, these phones appear to be in pretty good condition, and the seller seems to have pretty good feedback. If you've got the cash to spare, it could be pretty cool owning an unreleased prototype of the phone Google used when developing Android years ago, especially if the device still turns on and you can play with it.