I placed item on my watch list. Seller emailed with an offer and I acted on the offer: I bought the item at a slightly reduced price (very common on Ebay, right?)
Seller emailed and said she'd only sell at original listing price (after her offer and my purchase).
I suggested that she should talk to eBay and not me since the purchase had taken place.
She emailed cancelling the transaction.
Buyer beware.