Well, right now we only have one CS system, let's call it the Wal-Mart system. You see something you can buy, you can buy it immediately.

I would like to have some kind of eBay system, where you can bid on the items as well.
The items would be separated into two groups: The Wal-Mart system and the eBay system, and you could go to each section looking for better prices.

The advantage of Wal-Mart system: You get the item immediately.
Disadvantage: If you are the seller, you could possibly get less money.

The Advantage of eBay system: As the seller, you get more than your listed sell price if you get a bid.
Also, if you are a buyer, you may be able to jump on something nice for a much lower price because the seller may want to start his price at a much lower price to entice bidders.
Disadvantage: If you are the buyer, you do not get the item immediately.
Also, you could also overpay.
Also, since you don't get the item immediately, you can't jump immediately at the item for a low price, since it's bidding.

Please Please Please give us PleBay!