In my experience you need to find a local LARPing group. I have a few to chose from in my town (Colorado Springs) and each one uses a different set of rules and guides. I know there are A LOT of books out there for LARPing. GURPS has rules for LARPing, last time I checked. As for gear, I have seen everything from guys using bed covers to people like me, with way to much free time, and a bad sense of budgeting that spend thousands of dollars on period specific equipment. I have only ever spent about 400$ for an entire “character.” But some of the knights I play with actually forged their own Full Plate from steal. One suite actually weighed 200 some pounds and this guy wore it like it was a feather. It really all comes down to what kind of LARP you are looking for and who you are going to be playing with. I always play VTM (Vampire: The Masquerade [Old School]) with my friends, so all we really need is a set of fangs and some fake guns and some daggers, and lots of “Hot Topic” clothing! My recommendation is to find some local groups, check them out in person, see what they have to offer and then go from there. The other option is, if you have the friends for it, start your own group and pick out a good LARP. Your local game’s corner\nerd hoard\geek temple\comic book store will have plenty of resources to pick from. The final option is to make it up yourself! I and my friends took D&D 3rd Edition and turned it into a LARP from some of the local kids to play and act out, and it worked really well actually. Hope that helps some how, let me know if you want any kind of follow up.