I would just buy them. Don't expect them to go any lower than like 75m. They aren't that common from gacha it's just that over the years people have been getting them and they all flooded the market at the same time. Eventually the supply will slow down and they'll begin to rise very slowly.
@drager260 I thought these tradable ones were new or something and that's why they were flooding the market? @Aeronomx Yes, it's essentially the lvl 70 DB mask except completely tradable with no restrictions and 5 slots on it.
@anthony74 It's just the quality purple mask that we've been getting from gachapon for years now. It's just that the trade restriction has been removed. I had 3 of them from years ago and managed to sell them for around 600-700m each before they crashed in price.