Wanting to Race

Hello. I’m wanting to start to race. My stepdad raced a lot before and said that I would be fine. My dad says the opposite, the thinks that I need to rebuild my 01 400ex after every race. He thinks I’m going to spend $700 in race fuel for every race. If I want to start racing, what are some needed mods and how much should racing cost a weekend doing cross country racing. Thanks!