A fun article on cheap kitchen knives and end of the world survival can be found here at the Bison Survival Blog.
If you haven't done it before, I highly recommend walking through your friendly neighborhood dollar store (a great place for budget preps to begin with) and looking at what could serve as makeshift weapons. If anything, it gets the creative energy flowing. I'd also recommend garage sales and thrift stores for the same thing. Give yourself a $5 budget and see what you can come up with.