Subconsciously 12.99 is more attractive than 13
12.99 or 13 it's the same price
Bad trick, an effort to convince me that I pay less while I pay the same price
For one CD it's not a big saving but as I used to buy CDs all the time and I have hundreds (thousands) CDs in my collection, I save hundreds (thousands) cents, so why not to prefer 12.99 to 13...