I prefer how Eve Online do its market, and that game is well known for having the best player-run economy and market in the industry.
Having it your way @Lillith where you list multiple stacks could lead to a mess of things? Multiple listings of single stacks.
You could have 1 large stack of 100 and tell the system you pay x coin per x qty. And you buy 1 or 5 stacks directly from that listing.
Or, you set 100 items, and you have a minimum qty you need to commit to in a single purchase before you get the discounted rate.
It’s the same with fill requests. You could offer a better rate for people selling to you a minimum qty at a time instead of 1 at a time.
Either way works of course.
World of Warcraft Auction House Screen
In this image, you see most are single items, and the last one, the Darkmoon Firewater has 3 qty available. But no stack price, which would be nice.
Screen of Eve Online Marketplace
Obviously, this screen is much more advanced and shows you direct competition in each market. Not how we want our market screens to look (I personally like the feel of the WoW auction houses but want to use a blend of what Eve has in terms of flexibility with fees and owner control etc). But you can see on the left you pick the item (and items not in that market are filtered out), and on the right, you see the listings, qty, prices and when the listing will expire. You as the person who listed your items for sale or purchase can adjust your listing pricing as you wish and compete with other listings live.
Contract screen for ‘stacks’ of items for purchase or sell.
Eve Online has then taken it further when you want to do what you are saying @Lillith. They have a ‘contract’ system that is separate from the market. You list a ‘stack’ of items, whatever they are (think of it as a container of items), it can contain a single stack or multiple stacks of different items within. You list your price and the pickup location.
You can also do the same with request contracts. You want a stack of items or a bunch of items and this is what you will give in return for completing that order.
I think we could do all this with our market system? (just formatted nicer)
When you visit a market, the screen on the left lists all items with a listing associated with it. When you click an item, it will list all sellers and buyers of that item in that market. You can buy directly from there, sell directly from there, or create buy and sell orders directly from there.
The main market in-store, instead of listing just what’s in that one market, will list what’s in every market in-game and will teleport people to that region when they are interested in buying. The main market will not list its own items.
Now, in terms of ‘contracts’, eve online goes one better. It does not only allow you to set a ‘price’ in currency, but contracts allow you to set up trade requests. You can tell the system, I will give you 50 wheat flour if you provide me with 100 wheat. Do you want a stack of 50 wheat flour? I will take x coins, or in another contract, I will take 100 wheat. Or perhaps I will accept 90 wheat and 10 coins, whatever you wish.
We could build contracts into the markets in a tab just as easy, and that will have the features you are asking for? The same thing in the main market, it can list all contracts available in-game and teleport the player to the respective area to go make their purchase and claim their items.