From the Xtracycle website:
With a bike trailer, you'll leave it at home because you prefer the way your bike rides without it, then later wish you had brought it along.
Great, I'm sold! Except... College... Money.... Oh yeah, lackofcash-itus :( Here's my $10 solution for a great idea!
Sorry Xtracycle guys - At the moment, I just can't afford to pay for the engineering :(
Step 1: Materials
Grade 8 Bolt