In Australia we know Toll Free Numbers as 1800 numbers. Toll free numbers are phone numbers that are free for the customer to call, at least from a land line. There are big benefits for companies with toll free numbers as customers are more willing to call and generally this means you will have a higher call volume.
The major downside to a toll free number is that all of the call costs are passed on to the business so if you are a small company this could be cost prohibitive.