Archos has released the Arnova 7: a 7-inch resistive touchscreen tablet (800 x 480 resolution) running Android 2.2 (codenamed Froyo). It costs a mere $100, but given that you won't be able to access the Android Market, we're not sure it's worth it.
Other specifications are scarce. We know comes with 4GB of flash memory, which is extendable via micro SDHC Slot, and that it supports 720p HD playback, but the processor and amount of RAM are unknown. The battery life is supposed to be available, but it appears to be (accidentally?) omitted: "Video playback time: up to hours" and "Music playback time: up to hours."
While we haven't reviewed this device, it's already very hard to recommend. First of all, it's not running the tablet version of Google's mobile OS, Android 3.0 or Android 3.1 (codenamed Honeycomb). To make matters worse though, it isn't even running the latest release of the smartphone version: Android 2.3 (codenamed Gingerbread).
This is part of a bigger problem that Google has with its Android operating system. The search giant has no way to enforce what version its partners choose to release their devices with. This results in a poor experience for users, and as a result their opinion of Android is not very good.
If you really want to cheap out on a tablet, wait for India's $35 version. That being said, if you're going to go with Android, we really do recommend going with some version of Android 3.x. The cheapest around seems to be the Acer Iconia Tab A100 for $350.