$500 can get you a decent starter gun, battery, charger and some mags. From that point on it's all gear. You can get a BDU at a surplus store under $100. Get a good pair of goggles, boots, knee pads (they're more useful than some might think) and a vest, and you're up around $750. Anything else from that point on isn't necessary. However the more you play, you'll find things like a drop pouch, radio, headset, etc to be quite useful. So that can easily bring you up to the $1000 range. Then you'll be fully geared up and ready to go. But for a full basic setup, you're looking at the $750 range.