Is this discount phone service a scam

Is paying $14.99 per call to the phone service at the jail a scam? The discount phone service gets a telephone number (forwarded onto your current line) that reduces what the prison phone service can charge you. All it does is save money, the phone companies hate it and will tell you it's a scam while they are taking your money in big piles for simple 15 minute phone calls because they have a monopoly on the service to your inmate. If you talk to your inmate more than once a week, this is a fantastic money-saver for you.