Here's one thing that you can buy for five bucks that'll make your life instantly better: a 10-foot long USB extension cable. I swear—this is not hyperbole here—buying one of these cords will change your smartphone using habits as much as buying a new iPhone 5 would, for a fraction of the price.
For a while I carried a USB drive on my keyring, but it never helped me rescue a computer lab damsel in distress like I had hoped it would. Maybe I'll fare better with Scosche's FlipSync folding USB key fobs.
There are USB cords and there are USB cords...and there are USB cords with like 10 different adapters coming out. But rarely are such monstrosities this cheap.