Unfortunately a PSD is not a design, esp. for a website, but I'm sure people will find that out if they choose to buy them - I think a better model would be to offer to sell services, not a 'design' which, while pretty, is static and probably in many respects wrong.
Design is a process and a way of thinking, not decoration.
(BTW, turning a PSD into a website should be kinda hard for folks that don't work that way).