The game has an automated auction house that will update once an hour with a new item up for bid. In order to bid you will need some allied notes, commonly obtained from portal battles. Once you have some and feel ready to participate, look through the commands here and join in.
!auction info reveals the auction information. It looks like this:
BattleArena: [Auction Number: 2] [Item Up For Bid: RottingMeat] [Minimum Bid: 150] [Time Remaining (approx): 37 minutes]
The auction # is just how many auctions the bot has done since the Auction House has started. The minimum bid is the lowest you can bid on the item. Time remaining is approximate because it requires a battle to end before it will end and refresh/start a new auction.
To bid in an auction, enter !auction bid amount. You can only bid once per auction, so make sure you put the amount you want. You can't have negative numbers, decimal numbers (so no 150.5) or bidding more notes than you have. Also, bidding locks your allies notes in place meaning you can't spend them in the store. So only bid once you're sure you won't need the shop for the duration of the auction (will be an hour on the official game). It has to be done this way (at least for now) to prevent lots of errors popping up.
Something else to note is that auctions are blind. You will never know if anyone else has bid on the item or how much they have bid. So if you see an item you really want, take into consideration that you might be competing with all the other players or you might be competing with no one. Bid what you think will win the auction.
If you win the auction and you're logged in when the auction ends, it will send you a private message telling you that you won. If you're not logged in or didn't win you won't receive any messages.
"But Iyou, how will I know who won if the bot doesn't say it in the channel?"
!auction winners [#]
The bot records every auction's date, time, winner (if any), the item being bid on and the price (if any). If this command is used by itself (!auction winners) it will display the last 4 auctions, even if no one bid on them.
Iyouboushi: !auction winners
BattleArena: Auction No. - Date - Time - Winner - Item - Notes Paid
BattleArena: 00001 - 10/11/2013 - 22:38:20 - Iyouboushi - SpheroidPlate - 501
BattleArena: 00002 - 10/11/2013 - 22:43:26 - Iyouboushi - RottingMeat - 151
BattleArena: 00003 - 10/11/2013 - 22:45:19 - No Winner - BloodyHeart
BattleArena: 00004 - 10/11/2013 - 22:48:23 - No Winner - Bruce'sJuice
You can add in a number to check on a specific auction number (which makes it convenient if you need to leave and want to check to see who won the auction you bid on).