It happens every so often... I get asked if I give volume discounts for art/design.
I price my designs individually, based on their complexity. If a design contains at least one original illustration, say a car, it will probably not cost less than $500 and most likely cost more than that. In order to fall below that number, you'd have to settle for an already drawn and used piece of art from my files. Complexity, (hot rods with exposed engines and flames painted on the sides take longer to draw than, say, a stock Fox-Body M.ustang*) copyrights sold, time frame... all of these factor into the cost and each design is priced accordingly.
These are not items I buy wholesale from a distributor and stock on a shelf, each one is made by hand and takes many hours to create. Unless I'm using the first design as a template and just plugging new illustrations into existing layouts, two new original designs take at least twice as long to do as one, three takes three times longer, and so on. So I have to charge accordingly, otherwise I'm working more for less and I'm not gaining anything by getting more work from that client.
The works suffers as well... if I were to offer discounts to one client, the clients who are paying the full rate will get priority of my time. Discounted jobs will sit on the back burner until "I have time for them" and corners will be cut to fit them in.
I don't blame clients for asking. Everyone wants a deal and that's okay. I also have no problem working within tight budgets if the client is willing to settle for less detailed work, re-used art from my stock files or has a relaxed schedule. But offering discounts for higher volumes of work, or doing work on discount for more promised work in the future, are bad business practices... for both the client and myself... in my experience.
What do other artists do when asked these questions?
* Look what I had to do there. Really, people? Is it still that bad?