1) No idea, just be aware that when you’re on a motorbike you are very exposed and vulnerable to other drivers, no matter how good driver you are, others errors is in this case more of your problem than theirs.
4) Invest in gear that feels good, go to a store and try out some different brands/models. Buy what feels like it could stand a crash and make sure you get the right sizes, the protectors shall stay in place. If you go with leather, know that it stretches with use and that most leather wear is usually uncomfortable at start (good thing if you can try it on sitting on a bike)
I belive that Ben (the site admin) payed about $800 for his gear.
I myself payed about 1000$ for helmet, pants, boots, gloves, balaclava and back-protector. But with the dollar being so low, and me living in Europe I guess what Ben payed for his gives a better picture.
Welcome to the forums and good luck!