Those Bug Labs open source modular gadgets—the ones that you can buy in pieces and build your own gadget with—have just gotten pricing and availability details. They're also announcing a Von Hippel module, which allows an I/O interface so you can "further" hack your BUG. If you buy the modules in the first 60 days, you'll get a discount off of the already fairly reasonable prices.
• BUGbase - $349 ($299 w/discount)
• LCD module - $119 ($99 w/discount)
• GPS module - $99 ($79 w/discount)
• Camera module - $79 ($69 w/discount)
• Motion detector / Accelerometer - $59 ($49 w/discount)
All these will be shipping in Q1 2008, and be served in a first come basis. No pricing yet on the Von Hippel unit (named after the MIT professor and author Eric Von Hippel).