I might start selling off my collection of mission patches (and I don't mean the ones I designed, ones that are either official or designed by other fans. I'll gladly sell the ones of my design too, but I mean I'm pretty sure that ship has sailed)
like, from what I can see, a genuine Falcon Heavy demo patch is going for $80 USD on ebay. I have other miscellaneous patches that aren't as common as, say, space shuttle patches, like ones for Cassini, Chandra X-ray Observatory, Mars Odyssey, Mars Pathfinder, Mars Reconnaissance Orbiter, and a really cool NROL-22 patch I got from a former ULA employee (even though this mission predates ULA) that I can't find when googling it (never mind I found it, though it look like a different make... either I have one from the employee batch... or a cheap knockoff lmao)
I have a lot of others, but they're more common and relatively easier to find