Suger, you´ve asked exactly the same question in three different threads. If you post a question in the forum and feel that no-one has replied fast enough, please click Moderators on the bottom of the page and cat-mail your question (or send the page link) to any moderator who shows as "Currently Signed In". Your question will be answered as soon as humanly possible. 
Each skin costs 500 points per cat. Therefore if you want a red skin for each of lovely Suger and Splanda, it would cost 1000 points. If, for example, you choose a red skin for one and an aqua skin for the other, the skins cannot be switched from cat to cat. However, you can change each skin back and forth to default white. 