Bukkit

So, I see that many people are afraid to put sell tags, because it could make them bankrupt.
I had a similar problem once, when I lost 80% of my wealth due to a chest (now) full of wool.
Although this could be considered an exploit, it is a valid mechanic of the plugin. Which can be controlled.
How I do it: I fill a 27-stack chest with 26 dirt-pieces. Now, if I want to buy diamonds, all they can sell me is a single stack, after that a chest is considered full. I have a 70-item shop, and if I had empty chests, I would go bankrupt in a minute, because everyone wants to sell.
But, I blocked all of the excess slots and viola: I can no longer go bankrupt.
I also have a chart, to indicate all my current and total possible expenses, as well as possible incomes.
http://img850.imageshack.us/img850/3280/chestr.jpg
Please, take your time to include this is your description, as it is usefull information.

Sidenote: Your plugin is perfectly simple, a sign and nothing more. Please dont include any banks and stuff, it would make it too complicated.

Yeah, it's a valid method, however it's more of a work-around the problem. I am not going to introduce banks, however there is going to be a shop database (it will be invisible to the player, anyways - it'll be there only for development purposes).

I prefer to look at it more like a "perfectly simple solution", than "workaround".
You just need to note this possibility in your description, so that the players can use it.

You see, if you introduce databases that contains additional information, that means that the slightest error could corrupt/bug/delete everything. (I've had my fair share with such plugins.)
I consider a logging/statistics feature the only thing missing.

@stgram: Go It's already noted in the description :)

I have a group of morons trying to break my economy with multiple accounts. Is there a way i can get ALL chestshop sales to shop up for OP and ideally admin via a perm node? i've had a look and not see it in config etc.

@ManBeastPigDev: Go

You could simply set the ranks so that they can't create a shop until they prove themselves to be a valid account in some way, and not just a multiple account.

@ManBeastPigDev: Go

Sorry for late reply, but there you can use IP-Check plugin...