If someone hasn't made a 3D printable model for IR glasses I think I may make one this weekend.
With a model file, 20 cents of filament, a few LEDs, some wire, and a watch battery these could be made DIY for a few dollars after the printer cost. You can get a decent 3D printer for 200 bucks these days.
They won't be as stylish, but they'd do the job just fine.
Honestly, I don't want to manage a battery. I would maybe be okay with it if I could recharge it wirelessly (set it on one of those wireless phone chargers or whatever), but that's a bit outside DIY ATM.
But yeah, spending $100+ on glasses just to piss off some security guards is a bit steep. I'm at a point where I can absolutely afford it for the lulz, but that's a pretty big ask for the type of person who would be racially profiled away from the store. I wish I could just grab any pair of glasses ($10 or whatever) and spray on some kind of coating to get IR reflectivity. Maybe that exists, I just don't know enough about it.