What is the average percentage of commission for a commission only
salesperson in the Greater Cleveland, Northeast Ohio area?  Do
commission only sales representatives ever get benefits of any kind
such as health insurance, etc., paid by the company they represent? 
On an average do commission only sales people ever represent more than
one company at a time, possibly even companies that sell the same
products/services?  Thanks!

I belive comissions range from 2% to as high as 25%. Commission-only
sales reps RARELY get benefits such as healthcare, 401K, etc. because
they are billed out as independent contractors. Many businesses find
it in their best interest to hire commission-only sales reps as such.
The best of both worlds might be to find a job with a base+commission.
These companies have your best interests at heart, but often have
lower commission rates (2-10%)

Hope that helps!