As far as signing up goes, I only ask that you conduct yourself in a responsible business like manner and treat people right. You don't necessarily need cash or credit to do this business but it helps and as with any business it is vital for long term success. Also those that are starting out and have less resources are often able to help distressed sellers more as they have more time and patience to help and find a buyer or work on tighter margins.
That being said, I recommend to everyone to do this business part-time for as long as possible and develop consistency and a track record of producing results (profits) before jumping in full steam. I wrote an article concerning this titled "Quit Your Job and become a Real Estate Investor"
It's the first and only one I have written, I will write more some day.