Referral bonus illegal?

[Fabio Secaira]

Hi All. Quick question for the more experienced among us :) 

I was about to have some biz cards printed and on the back we're stating something that prompts the following question: is offering a $500 bonus for referring a homeowner whose house we buy (or wholesale) illegal? I read somewhere that it may constitute acting as an unlicensed agent. 

Thoughts?