OK thanks Eric.
Someone is selling a domain (it's in a list of domains that was posted on March 5th) in the Make An Offer forum (still open). They then posted the domain in a somewhat similar list in the Bargain Bin forum on May 30th (closed). Then they posted it by itself in the Domain Auctions forum on June 26th ($50 starting bid, thread is still open but the auction has expired).
When their Bargain Bin thread was open I hesitated in buying it and lost out at that $20 price when the thread was closed. I PMed them about me buying it at that price and they told me they wanted more, which is their right of course since the thread was no longer open and valid.
I'm going to offer them $20 for it again and am just trying to figure out how best to approach them about it.