Toll Free numbers, whether used by a business or used in a conference bridge, mean that the callee pays for the call. So as the host of the number all minutes accrued are charged to the business and at a higher rate than normal long distance.
When the caller is using a cell phone they are charged for their minutes regardless of whether they are calling a local, long distance, or toll free number so the cost convenience of a toll free number is not realized by the cell phone caller. If the caller is a business line they are typically on a phone plan that offers free local/long distance, a VoIP plan that is billed similar to cell phones with all minutes being minutes, or have packaged minutes that are typically far in excess of what is used every month which also results is an unnecessary toll free expense to the callee.
To toll free businesses this can add up to thousands of dollars a month in unnecessary expenses. What should businesses do? If you are pushing a nationwide presence then a toll free number is still en vogue. It doesn't pigeonhole your business to a region which is the desired effect. For other less visible lines such as local calling areas, regional offices, and conference bridges, businesses should consider using local numbers to eliminate toll free costs without putting undo expense on the callers as they will be using their minutes regardless of the number they dial.