If you are dedicated it won't take you long. I got into this about 2 years ago when I was 12. Within 6 months I had a HAM license and a bunch of gear. If you stay focused it will all come together quickly.

I suggest first getting at least 300 rounds for your AR-15. Go to a gun show to get it cheaper than a store. Grab you a "game bag" from Academy to keep some basics in such as a flashlight, a cheap walmart sterno, some beans, a cigarette lighter, cleaning supplies etc. Also get you a few camo clothes cheap at walmart. Go to the store and buy an energy drink with an aluminum casing, drink it and use it as a canteen. Buy something to hold magazines in from Cheaper Than Dirt because they are cheap there. Grab a compass for cheap somewhere, find some maps online.

I find the best way to find things you need is to keep a pad with you, for 2 days make a list of every item you use that you NEED to have. Go get those items.

Good Luck