Looks like Tina gets the sale then, must be taking a loss on those suits or spending an excessive amount of time farming mats.
Hera, I don't have my vendors up anymore and, as Czarina suggested, when I did have them up I was spending the majority of my playing time gathering materials. The only materials I've ever bought on Siege are a few relic fragments to make soul forges and a very, very occasional weapon. (I also bought some deeded gems when Doive sold a bunch of his stuff.) So whatever I sold suits for, the whole price was "profit" in a sense.
Also, when I started my suit vendor a few months ago, I was trying to match as closely as I could what everyone else at the time was charging. (For example, I think Petra was selling barbed leather 100% LRC suits for somewhere between 15k and 20k. I think Ginsu's most expensive LRC suits with more mods/resists at that time were maybe 90k or so.) And my shop was in Zento, which no one goes to anymore anyway. So you can probably get away with charging more than I was, especially if your shop happens to be in Magincia. I don't have any plans to reopen a suit vendor anytime soon so don't worry that I'll be undercutting you if you decide to charge more than I was!