Building robots has never been cheap, which sucks, because all that time and effort and expense that goes into building a hardware platform eats up all the time and energy that you'd probably rather spend making that hardware platform do something useful and cool. Part of the point of PR2 and ROS was to remove this hardware barrier and let people start focusing on software. Every once in a while, though, you run into someone who for some reason can't find $400,000 between their couch cushions for their own PR2. For these unfortunate souls, a new option may be the Bilibot.
The idea behind the Bilibot (which is some variation on "cheap robot" in German) is to create a robotics platform that's cheap enough for just about anyone to be able afford, yet capable enough for serious robotics researchers to be productive with. It consists of three primary components: an iRobot Create base to let it move around, a Kinect sensor to let it see where it's going, and a computer pre-configured with ROS. Part of the appeal of the platform is that it'll be capable of doing stuff right out of the box: there will be a single button you can push to get the robot to start following you around, for example.
The primary reason you might want a Bilibot is that the target price they're shooting for is a scant $650, which is basically just the cost of the parts plus the time it takes to put the thing together. And if you want to go even cheaper, you can build it yourself, the plans will be freely available.
Want in? They're currently finalizing the computer hardware, but you can sign up to be notified when pre-orders start for real at the website below.