Buy a color Barnes and Nobel Nook for $250 and a Class 6 Micro SD card, and you can have a dual boot Nook eBook reader and Android 3.0 (Honeycomb) tablet. We are in the process of doing this, and it works great! With the card in, the Nook boots to Android 3.0 and you have a great functional tablet, complete with WiFi. Pop the card out, and your Nook boots as normal and you have a great Nook eBook reader.
Follow these directions: Here
This is very easy to do, and works well. The toughest part is getting the market app installed. We are still working on that, even though the directions tell you how... we are still having a few issues getting it to work. We have been amazed at how responsive the Android tablet is running from the micro SD card.
This is probably the cheapest way to get not only an Android 3.0 tablet, but also a great eBook reader at the same time!