Meanwhile, back at the $50 question:
This is $40 ($60 complete with an Arduino compatible): http://arduino-info.wikispaces.com/BrickStarterSet
Just click on any Electronic Brick or part for How-To Information and example hookups and Software Sketches.
Just starting out?? Maybe start here: http://arduino-info.wikispaces.com/GettingStarted-Software
Comments, suggestions, critiques really appreciated! terry@terryking.us
DISCLAIMER: I mentioned stuff from my own Shop...