I'd wait until I can afford it, if I were you. When you get chickens, you need to make them as secure a home as possible, especially at night. Even if you plan to free range all day, you have to keep them safe at night. And even if you plan to free range, your predator load might make it difficult.
Have you tried Craig's list or LSN for used supplies? What about bartering? Junk yards?
I don't know what's less expensive: hardware cloth or 2x4 inch welded wire. But both would work. I have 3 dog kennels attached to each other consecutively, with that netting over the top. However, I have large noisy dogs and have been much luckier than my neighbors as a result. the problem with the dog kennels is that a raccoon can get his arm in there and grab a chicken, but my chickens sleep in the henhouse. Same for 2x4 inch welded wire. It kind of depends on your setup. I've never worked with hardware cloth, but IIRC it's smaller and more difficult for a raccoon to sqeeze his arm through. Just giving you ideas...
I don't know what you would do about them climbing up the 4x4s. They climb up everything. You just have to make sure that whereever they're climbing, they're not getting in a weak area that they can sqeeze though.