A toll-free number is a number which you can call at absolutely no cost. You must have come across many businesses offering toll-free numbers. The last time I saw one was on a Sprite bottle.
As a VoIP service subscriber, your service provider can get you toll-free numbers. If you have one, anyone in your country can call you for free. I mean, free for them, not for you. You may want to get a toll-free number for your business if getting customers to phone boosts your sales.
The owner of the toll-free number pays a monthly fee to their service provider, which is around $5 in the US. This comes with a certain number of free minutes for the month. Additional minutes are charged at around 5 cents each.
A residential user can have a toll-free number as well. For example, if you have many kids studying away from home, you can get them a toll-free number and save them from spending on talking to you.

