Well, for braking world records, you need quite a lot of money or sponsors who give you hardware, but to make them interested in what you are doing you have to show them that you surely can do extreme OC.
So at first you need lots of money for buying everything on your budget, and that will be expensive because you need high end stuff. So we are looking at $3-4000.
I don't want to discourage you, but it is a long way to become a professional overclocker.
I myself like overclocking and playing with the multipliers and baseclocks but I could save or spend that money on something else. Having said that, I have just ordered a RIVBE and an E5-2670 yesterday, obviously not for OC but it was cheap and I couldn't resist. They cost me £350 in total. So if you like tweaking and you have money you can and will become a good overclocker but unfortunately it is hard to start.