Been over 20 years since I worked music retail but back then cost was the same across the board for all retailers, but the mark-up differed greatly from store to store (a&b sound and Future Shop would sell CDs below cost and make up the margins on their electronics - which really fucked the game for the smaller shops who had to sell for MSRP, or closer to at least) but there would be additional discounts and kickbacks for bigger bulk buys as well. So if it's the label raising costs, it'll likely affect all shops but look a bit different based on buying power and the ability to absorb some of the difference or not.