Define "big time"... from the stats I have so far, a bit less than 5% of my referred ones make up about 90% of all referral income. You can have 1 mBTC if you like once I see you actually start using the account (most people who sign up don't seem to do anything with it) and you gather 1 USD for me (=10 USD fees paid).

Beyond that... sorry, but you are already getting a 10% discount for a month and I luckily still make much more on actually using the platform instead of refspamming (my signature is the only place where this code is displayed). I'm not going to start luring people in by offering special boni, since from what I see they would likely not be worth the effort.