Ask around, too. Your reptile store might have used cages for a big discount or free. All the stores I go to seem to have used cages on sale (and, I mean really on sale) at least a few times a year.
The local high school/ middle school science teacher might be able to loan you cages for awhile or sell you some for cheap (I say that because when I moved away from a big screen cage to a reptarium, I contacted my daughter's science teacher from middle school to see if he wanted it...nope, he was overly cage rich and couldn't take it.)
You might even contact lllreptile (board sponsor) and ask if they have any used cages available. They always do in the store when I go.