RallyGuy beat me to the punch, I was going to suggest the same thing.
I would also suggest that you crunch the numbers on set up time for each design. You can clearly make enough on this that, if you wanted, you could waive the setup fees, but be sure to let them know the discount they are receiving so that they are aware that they are getting a good discount on this order. Everyone likes to save money and it would look good on you that you are working them a good deal. Eventually those pens will be gone and you will find yourself with another order for 2400 or even more.

"If we ever forget that we're one nation under God, then we will be a nation gone under". ~Ronald Reagan