Perhaps you could buy a used one. Sort of like buying a used car --- something good that was treated well by the owner and doesn't have too-o many miles on it.

Besides this site (backcountryforum.com), there are forums for buyers looking and sellers offering on whiteblaze.net. I think BPL charges to list things on their site, but there may be others.

Or if you live near an REI store, look for their sales, including members only "garage sales", anniversary/coupon sales, etc. If you're patient and have an idea of several common pack types that would work for you, you might get something at a good price.