Provided that there are ever rare ships/items introduced to this game, I would suggest an auctioning system where people from all over come and join a particular Station's Auction Area. The Auction area would be in 2d on the PDA, and display a total number of seat to sit in. The more popular/prestigeous the station, the more the amount of seats. At each seat is a computer. Before you can "sit" in the seat, you would have to "register" and the computer would check how many credits you have; it would then subtract that amount from the percentage of "rake" which is taken out of the final sale. The station would keep the "rake" to itself for future station development, or trading investments. A computer would then start the bidding. If when you are in the middle of the auction, the price goes over your total amount of credits, you can watch, or leave, but you can't bid anymore. People will have bidding wars and skyrocket the ship/item's price. To determine the winner, each bid has a time limit of 10 seconds or so. After the ten seconds are up, the previous bidder (or second highest bidder) can "elect" for more time to think about it (up to one minute). No one can elect more time more than once. No one else can bid during this time except the previous bidder. If he doesn't bid, the auction is over. If he does though, it goes back to the 10 second rule, unless the "new" previous bidder wants to elect his one minute. Either way, this should end up to be pretty fair, and the auction should end in a reasonable amount of time.

I figured this could be one of those thing we could all spend millions on easily.

1. Sounds like it should be already suggested
2. Why so much overcomplicating? WoW-like AH (local for every station, of course) would be fine
3. IIRC in far distant impossible future players will be able post their missions, so if you need something, you can post a procurement mission.