How much should I charge for a house design/construction drawings that I have already done once before?

I recently designed a 3000 s.f. house with construction drawings that another client would like to build. Because I own the design, I can sell the already completed drawings. But what do I charge...I am essentially selling something that the work is already done. Any thoughts on this would be appreciated.

Public Comments

1. Standard amount that you charged before, assuming that you'll make any design changes to be site specific. I'm a professional engineer; sometimes I lower my price depending on the customer or work involved, but I keep it high enough so that they appreciate the effort that has gone into the design - whether it's a copy or not.
2. 25% off