This is what you get when a bunch of students - some of them high schoolers —four of them from MIT—get together and make their own version of the Segway. It may look like one of those golf caddies on wheels but it works and it's cheap: check the video comparing the original Segway with its sub-$1,000 imitator.
The students' four aims were to make their transporter for less than $1,000 and 50 pounds, to give it lean steering and to be able to ride it through doorways. It's even got two cupholders! [The DIY Segway]