Since Ledger's accounts and commodity system is so flexible, you can
have accounts that don't really exist, and use commodities that no one
else recognizes.  For example, let's say you are buying and selling
various items in EverQuest, and want to keep track of them using a
ledger.  Just add items of whatever quantity you wish into your
EverQuest account:

@smallexample
9/29  Get some stuff at the Inn
    Places:Black's Tavern                   -3 Apples
    Places:Black's Tavern                   -5 Steaks
    EverQuest:Inventory
@end smallexample

Now your EverQuest:Inventory has 3 apples and 5 steaks in it.  The
amounts are negative, because you are taking @emph{from} Black's
Tavern in order to add to your Inventory account.  Note that you don't
have to use @samp{Places:Black's Tavern} as the source account.  You
could use @samp{EverQuest:System} to represent the fact that you
acquired them online.  The only purpose for choosing one kind of
source account over another is for generate more informative reports
later on.  The more you know, the better analysis you can perform.

If you later sell some of these items to another player, the transaction
would look like:

@smallexample
10/2  Sturm Brightblade
    EverQuest:Inventory                     -2 Steaks
    EverQuest:Inventory                     15 Gold
@end smallexample

Now you've turned 2 steaks into 15 gold, courtesy of your customer,
Sturm Brightblade.