Free. Current version average rating: 3 stars Designed for iPhone, iPad
The Line2 VoIP service, which costs $10 monthly, adds a slick business call center to your iPad or iPhone. Line2 includes such business phone features as call waiting, call transfer, and multi-party conferencing as well as optional features that cost extra such as auto attendant and virtual receptionist. Call quality, in my experience, is quite good. You can also port an existing number to Line2, send and receive SMS, and use a Bluetooth headset on a call. As its name implies, Line2 is an ideal way to add a second, dedicated business line to your iOS device while keeping your iPhone number for friends and family. Heads up: You can't make 911 calls using Line2.