Recently I dropped sprint and started winning the game. You need to buy an ooma telo
I have this now and pay less than 5 a month for unlimited calling. Requires inner webs.Ooma premier is about 15 per month and can do multi ring andmulti line. You can also port your number.
Ooma is top dog
http://www.ooma.com
Pro tip I got my telo on amazon for 129 a month or 2 ago and it kicks ass
Premier features
http://www.ooma.com/products/premier
I was way skeptical at first but now I don't know why everyone doesn't use this service