IMPORTANT: You are purchasing the templates ONLY. By downloading, designing and uploading your custom skin you are claiming full responsibility for all content submitted. Designerskins can in no way be held liable for any copy written materials submitted. By submitting your skin you are claiming to have full rights to their legal use. This responsibility solely remains with that of the template purchaser.
so going by that, unless you use some of your own original art, pretty much anything you send to them for printing would be infringing on
someone's copyright. Notice that the "Fire Warrior" skins are all Sephiroth from FF7, "Blue Fury" is Hitsugaya from Bleach, and then all the obviously labled skins in the 'Hot Games Titles' sections.
Personally, if they're willing to run such a site they should be prepared for any legal issue they may find themselves in, I wouldnt worry about purchasing just one skin.