I use ooma and am happy with the quality of service. You have to buy their hardware. You can connect it to a wifi router, but if you have a separate cable modem, it has better quality calls if you hook up the ooma to the cable modem and the router to the ooma. I recommend the premium service which is $15/month. It includes a very robust call blocking service, among other features. You can also have it forward calls to your cell; I have my phone set up to do this only when cable is offline.