I still see those in use at theaters, and for $5-$10, you'd be substantially short-changing the school. If that's all you intend to get for them, you'd not be making nearly enough to make it worth the trouble of trying to sell them in the first place, nor would you gaining enough money to buy an alternative for the school should the sale of these headsets mean they need to buy new ones in the near future.
If anything, I'd suggest an extended loan type arrangement. One theater I work at has a few movers they don't use often on extended loan to someone do the movers' motors don't cease up from inactivity. In this case, they're loaned out to someone with the understanding that they may need to given back temporarily or permanently should they be needed.
As for the whole surplus thing, some entities require used equipment be sold via a surplus service. Others don't really care and if a good deal among friends can one negotiated, a good deal is preferable. I have relationships with several TD's in the area where we've lent/sold/given to each other for cheap or for free based on the understanding that courtesy would go both ways in future deals and times of need. If anyone's business office asked, a good enough argument could be made that the deal was fair for the relationships built, and that the relationships of knowing if your sound or lighting
console tanks that you can drive down e
road to another theater and borrow one in a pinch is well worth it.
In your case, if your business office asked, you'd be in a terrible position. The sale of equipment for a rate you've determined from your job at one institution to yourself at another institution without someone else on the seller's side involved in the sales process would look awful if someone started asking questions. It could potentially be a fireable offense. Before proceeding, I'd doubly verify that you have the authority to make the sale and that even if you do turn out to have that authority, that a colleague who shares that authority with you vets your terms of sale first so if questions arise, you have something to fall back on.
I maintain though that if the school stands to make only $50 or so total off of your sale of multiple headsets, forget it. It's not anywhere worth the inconvenience to them should they decide they need them for a show down the
road. $50 doesn't buy a lot of gels or gobos, or even a single
microphone or replacement
headset. It's not in the better interest if the school to make the sale unless they are in such a position where those headsets cannot at all be use with any existing systems and are just growing cobwebs in a cabinet somewhere.
