Um, the $14 item is a rack. The cheapest panniers are $20, but are unsuitable for a laptop, as the OP requires.
The Daytrekkers aren't big enough (I own one I don't use and can't give away) and the grocery pannier (Townie Basket) has no top or interior retention system. (I gave mine away after I upgraded.)
I think a sale ended and the price changed. I still have a tab open showing the Daytrekkers on sale for $13.99, but when I open it fresh, they're now back up to $19.99.
And yes, the Daytrekkers are small, but they are the right size for the very small loads I typically carry. As I said, not big enough for a laptop, thus not big enough for many people.