Among the various scientific/industrial robots in the marketplace, Willow Garage's PR2 is one that stands out. This is because both its hardware and software are open-source - users are encouraged to share their latest upgrades and customizations with one another. With various parties using a common platform, instead of all having to start from scratch, Willow Garage hopes to move the field of robotics forward faster than would otherwise be possible. To that end, the company recently gave ten PR2s to groups involved in robotics research, to keep for up to two years. This Wednesday, commercial availability of the PR2 SE was announced. It costs US$285,000, which is significantly less than its sibling's $400,000 price tag - users will just have to work around the fact that it only has one arm.
Depending on what the robot is needed for, its being one-armed might not present any problems. Should users decide that it really needs another arm, one can always be purchased and added on later.
If $285,000 still sounds too expensive, then be aware that a 30 percent discount is available to "individuals with a proven track record of contributions to the open source community." That would lower the price to $199,500 ... and hey, perhaps another user might share a program that enables the robot to build itself a second arm.