Hello
Prob not posted on the right place, but I will answer it anyways
When people talk about "buying or selling" with escrow bassicly it means to use a third person on the deal which is trusted by both of them.
AN example of buying an item with escrow would be: (Imagine you use Ognasty as escrow, which is a very trusted member at the forum).
You send the money for the payment to Ognasty, when the money is received, seller sends item to you.
When you receive it, you test it and confirm everything is right, at that point, Ognasty releases payment to seller.
This adds a lot of security to the deal because in case anything happens money is not in sellers acc but in Ognasty's acc. (ex:sellers ships broken item), so you will be able to recover your funds by explaining everything to Ognasty.
Finally, People charge for this service around 1-2% of the total transaction, for their time. This is why sellers usually say " buyer pays escrows fee".
Miguelik