MindySue-
I'm not sure what professional backdrops go for, but if you look around on Craig's list or any o fht other sites, they can be gotten pretty reasonably.  Aside from that, just be creative... I know you can do lots of different things outside, or different fun locations.  Not sure where you are in PA, but I know there are a few charms in and around there.  Granted if your in Erie, it's a bit of a hike to meet one from say Philly.  It could be a way to "pool your resources"
just my two cents...
That and welcome to SC!  looking forward to seeing more of your pics!
			
		