There is a little caveat, but depending on the users seeing it some will give you a hard time.
You ARE allowed to post ebay auctions in the "For Sale" section only if they are YOUR auction, but definitely post that the items are yours.
The External site auctions,etc are mainly for other people's auctions you find that you think others may be interested in.
And yes, there is no FA, but since an auction will have a sales price I believe you would use FS vs MMAO, but those fine points are a bit lost on me.