Consider looking online. You could search different sites using froogle.com which is a division of google.
Your machine is a bilevel (called BiPap by Respironics), which is made by more than one manufacturer.
It's still expensive, but it's always worth a look.
Getting a machine locally has some advantages. But check around, talk to several DMEs (medical equipment providers), if you have several in your area. The costs may be the similar but maybe one of them could offer you a better payment plan.
You could check to see if there's a local AWAKE support group in your area that could give some pointers. You can find a list at the main site of the ASAA, www.sleepapnea.org
Maybe you could get some family to help you with the cost. Afterall, it's your health and they may be happy to help.