that's a tough one, especially in Portland right now where we have one of the highest rental rates in the nation. Obviously if you have to be in Portland, I would start for the outskirts. If you can move out of Multnomah County then try Clackamas, Marion, Yamhill or Washington. Also check with your local services for that county and see if there's any kind of low income housing you'd qualify for. Without knowing more about where you want to be near, its hard to answer. But the good news is, a landlord will likely like the fact that you're have a secure income even if its lower... it is consistent!
best to you