Write some Software

I want to create a referral tracking system that is 2 levels deep. Basically when A refers B, they will get x amount of money and their upline will get y amount when a certain criteria is met by B (this is tracked on a weekly basis and is manually updated by me). I'm not sure what is best way to do this either (I was thinking of a macro in excel) or through the web, but basically it doesn't have to be complicated. My requirement is that at any one point I need to be able to see the full tree with date signed up, some details (will provide later), and who referred them.