218-339-4300 is a free conference call service. There is no conference fee but each participant's reglar phone bill will include the standard toll call charge between their phone and the dial-in number. I've used it on three occassions for conference calls among our board of directors with no problems.
The calls you get are not from the dial-in conference service but from the groups using the service calling to invite others to join in. I've never been called (I call in), but that's the way it has been explained to me.