I just got a bionic on ebay for $160, mint condition, with all original box and accessories. Rooted with a custom rom I'm estimating 1.5 to 2 days battery life, I haven't done a full test though. If you're really going to be mobile with it and looking things up, you can get the lapdock and turn it into a pretty capable laptop.
The lapdock goes on sale from time to time, and last I read you can get the $350 model for $150 on verizons site if you do some trickery by adding the droid 4 to cart, then you get a discount on the lapdock, then remove the droid 4...