vendors suck I used to love to run vendors that was before luna! now they charge so much and if you dont have traffic this can get spendy fast You are almost better off spaming at the bank atleast then you are not paying for it!
I am only able to turn a profit because I am (relatively) very active, and set runes out at least twice daily. I have a small vendorhouse with six vendors on it, and none of it is higher end arties/rares. It is all basically normal or craftable stuff, that players do need/use, but which just don't have a huge profit margin built in. Recalls, runebooks, low end deco (crafted furniture and deeds, etc.) potion kegs (VERY tricky item to turn a profit margin on.... the cost of regs alone for the types of potions people will buy gets up into the 2000 range, figure like 300ish for the keg or making it yourself, and then people expect to pay 3600 or so for a keg... 4000's will sit and not sell for awhile, racking up vendor fees.)
So, I spend about 600 gold per day just on runes, and probably another 600-1200 on vendor fees per day. There are days I sell nothing, or make 250 gold in sales. Other days I make a few hundred, or a few thousand. But, it's tight. And I'm certainly not making a "living" off of it.
I wish, instead of flat vendor fees, there would be very low ones on everything except artifacts. Those are really the items people are abusing anyway trying to sell a darn Tokuno fan rarity 3 for 25k on their Luna vendor and it sitting there unsold for three months hoping some noob will buy it. Or things sitting on vendors for 24 million gold. Yikes.
With things like scrolls and potions, I'm ... if I sell relatively promptly... making a slight profit more than I'd make just dumping crafted items on an NPC. If they sit unsold for three days or so, which is not uncommon, that profit margin is pretty much gone. And it's much harder to sit in town and sell runebooks or potions than it is to sell a rare artie. I think vendor fees are a good idea, I just think that they penalize the wrong kind of vendorhouse people.