The most popular option is the Pay-As-You-Go plan. WIth this plan the cost is 5.5¢ per minute per participant. As with all conference call companies, conferencing minutes are calculated by multiplying the number of participants by the number of minutes of the conference call. For example, a 30 minute call with 5 participants is 150 minutes of conferencing. With the Pay-As-You-Go plan this call would cost $8.25.
There are Monthly Minutes Plans available if you do more than just an occasional call. They offer discounts as low as 2.5¢ per minute.