Here's my .02.
Rifles. Stay away from the Henry's. I have never seen one go through a match without breaking. 92's decent starter rifle, but you're probably going to want to step up to a 66-73 so why not start with one.
Shotguns. I've got SXS, 97s and 87s. stay with a system you have experience and feel comfortable with. Stay with 12 ga. If you are uncomfortable with recoil, there are very light loads available.
Pistols. You'll end up either a SAA clone fan or a Ruger fan. Let your prejudices guide you. Won't really matter in the long run.
Caliber. Stay with one of the common calibers to start. .38 spl/ .357 or .45 Colt. If you're recoil sensitive, stay with the .38 spl. KISS. Keep rifle and pistol in same caliber. You'll be reloading later and makes it easier to reload and keep track of one caliber.Learn to say .45 Colt instead of .45 Long Colt. It will save you unnecessary criticism later.
Reloading. No matter what caliber you decide on, learn to reload. Buy yourself one of the better progressives. I prefer blue, but your opinion may vary.
Leather. Really good leather is expensive. But you want good leather. keep your eyes open for used deals. You' find them here, on Ebay and other sites. Don't be afraid to post in the want ads here that you a re a new shooter looking for equipment. Stay with the top makers. Too many to mention here, but stay away from the cheap stuff listed on Ebay from Mexico.
Costuming. You don't have to go out and but a $500 set of clothes to start. Jeans, a button down shirt, western style hat and Cowboy boots will get you started. You can find stuff at surplus stores and make your own.
Extra Credit. Learn to say please and thank you. Learn new skills related to your new hobby. You can make a lot of your own stuff, whether it be gun carts, loading blocks or take up leather work and make your own holsters. Nice when you can thank someone by gifting something you made yourself.
HAVE FUN!!!!!!!!!!!!!!!!!!!!!!!!!!! If it's not fun, why are you still here?