I know that one thing my school is always needing is various sound or lighting adapters. Splitters, male-to-males, rca,
dmx. I know I could spend 150 on just adapters and they would all be used within a week.
Or perhaps some new shiny booth speakers? (I know all of ours are somehow yoinked from shanty bedroom boomboxes or computer speakers)
Some tie-line. For some reason none of the high schools I've seen ever have tie-line, and it's just so useful.
As for you, I would definitely second the idea of a nice multi-tool. I fell in love with my gerber years ago and it's still in excellent shape even after all my abuses. Perhaps a maglight too.
Ooh, or buy some fun LED pars. They're so easy to use and we've found so many ways to use them. 150 could probably get one, but methinks that two little lights would be a decent investment.
Or, if you want to have a little fun, glow paint. It's pretty well invisible under normal light. We just hid little notes in the scene shop for when the lights go out.
Have fun!