An obvious and blatant attempt to get hits on their listing. This is called keyword spamming - using irrelevant words to get
As we look more closely at the listing, we see the shipping is $9.99. For a 3 ounce baseball hat? And then when you look closer at the shipping section, we see that the seller is using Media Mail - which is a class of mail only for media products (books, CDs, DVDs, VHS tapes, etc.) So, the buyer will pay $9.99 for a 3 oz hat to be shipped for 9 -15 day delivery?
As a buyer, watch out for listings like this. If the seller is this unscrupulous with his listing, odds are that the item is not of top quality and you won't receive very good service either.