Need some ideas and input.

[Rangerdanger]

I would say to add something that could see if multiple people ARE trying to bid something up to ban them for the market thing.

Cause I could see it being exploited since Person A could sell something and Person B would then buy it higher then Person C would buy it higher then Person A buys it higher then sells it to a Person D (who is new) for an outrageous amount. I'm sure something can be made but would not/should not be top priority.

Another thing, couldn't someone 'corner' the market by buying up all of a certain type of gun? Since if you could buy lets say glocks, could someone buy up ALL glocks then sell them for an outrageous price?

I may be very wrong and you have already thought of this but I'm just pointing it out now rather than later.