Looking for an inexpensive readily-available Android tablet? Let me introduce to you the Pandigital Novel e-reader... erm... tablet. Pandigital made the wise choice to use Android as its system base, which was a pleasant surprise to the hacking community. And although originally intended to be an e-reader, the Novel has now been rooted/hacked to be a standard Android tablet. Specifically, the Novel can run "Vanilla-style" Android and third-party apps!
What do I mean by vanilla-style? Well, simply put, this is accomplished by running a home replacement (original one used for the demo was Panda, but I presume you can use any home replacement now). What's running isn't pure "vanilla" Android, because this would require a custom recovery and custom ROM to be installed on the Novel. Although rooting has been achieved, the community is having a hard time getting past that pesky bootloader, and as such, custom recoveries and custom ROMs are currently unavailable. On the other hand, the good news is that the Novel's Android base is 2.0 (original Motorola Droid users may remember this), so you're not stuck with archaic software, like 1.5 or 1.6.
And what about the technical specs? The Novel sports an ARM11 processor, 7" LCD Resistive screen, 800x600 resolution, WiFi connectivity, 1GB storage, SD/MMC slot (up to 32gb storage), and up to six hours battery life. Not too shabby for a tablet. So what about the price? The Novel retails for $199, but you'll be able to snag one of these as low as $129.99. However, from a quick Google search, the cheapest available now is from Bed, Bath and Beyond (for $169.99).
Hacking the Novel is not for the faint at heart, but those of you with Android/ADB/Linux background should have no trouble. Here's a nice walkthrough (w/ video) on how to root and hack your Novel: Hacking the Pandigital Novel (video) | The Digital Reader
Also, helpful to check out SlateDroid.com for access to the strongest Novel community out there. They need as many hands as they can get to fully hack this tablet!