Ad Block Plus is good, but during last weekend's listings, I found that it didn't prevent a very annoying pop-up each time I began a listing via "Sell Similiar" - when the new page opened and I began to type the listing title, a pop-up appeared from the "Condition" field  telling me what "Good" meant.

The pop-up had around ten different elements which had to be manually blocked, one by one. Next day, the pop-up appeared again - this time the blocks didn't hold, and it came up with every listing I created. Annoying!