Just Strings has D'Addario singles listed. Don't know if they have any kind of deal going on singles, I bought a few singles along with several sets recently , seems the opposite.
You're not talking just individual strings, are you?
I bought 10 sets of EJ16s (just the normal lights) on Amazon.com in a 10-set box (semi-obviously) for I think $44 or so. I thought it was a pretty good deal! It's a "pro pack" or something, I believe.