Food, water, protection from exposure, hygiene, information, and defense.
These are the key items. There are literally thousands of products on the market. Do your research, decide your priorities.
Even if you only buy one piece of gear per paycheck, you are better off than when you began.
But the most important aspect is TRAINING! Know how to use that gear, and know how to go without it. Learn all you can about survival, because you WON'T pick it up in the fly...