Sign up bonuses typically have so many strings attached to them that they aren't worth signing up and trying out the service to get them and most companies probably realize this so they don't bother.  The ones that do bother are probably filled with attempted scams, user complaints about withdrawal issues, and constant questions about how to withdraw the tiny signup bonus.  I can't imagine it's worth the hassle, but maybe for a company that already has this bonus in place it isn't a big deal.  Personally, I would be wary of any company that is offering me free money if I send them money first.  It just seems like a bad idea unless you already trust the company, in which case you probably wouldn't be a new user.