Looking around for cheapo strings I found La Bella 7-set while not cheap is 10-64 which is what I dig for drop-A. Anyway any of you guys used them?
La Bella Electric Guitar Nickel Plated Steel Seven String Set, .010 - .064, HRS-72
they have ones with a low 70 too
Amazon is usually great for inexpensive strings. I haven't heard very good things about La Bella strings. You might want to consider the Ernie Ball baritone set, and some Rogue bulk strings for the highest string. Just a thought.
Search Amazon for -> ernie baritone
and rogue bulk