We have a cheapo laser cutter off of Amazon but it hasn't seen use for months as it was run by my ex-coworker. We did use it for engraving chromebooks for a year or two but prior we were shipping chromebooks out to be engraved anyway. This summer will probably be the first time we seriously look at buy back but realistically we probably wouldn't get much back since most of the chromebooks are past EOL irregardless. We already have a mound of chromebooks that we were using for spare parts as well so really buy back is more about getting free disposal.
Anyway one of the reasons we haven't run the laser cutter since is we don't actually have a proper venting system for it. Before my coworker got away with it, at my objection, by opening a door and running a box fan but some recent remodeling has made that not viable and it was sketchy solution anyway. You'd probably want to look into what your local area/school regs require for ventilation (filtering?) and power. To do this properly will be expensive and it may just be better to out-source any engraving needs. I believe some white glove services include engraving as an option now.