That all depends on you. Are you a small business enterprise? A residence? VoIP has prices and features to suit everyone. What provider is best for you may not be best for everyone.
Service matters. Price matters. Terms and conditions matter. Be informed and read reviews. Compare providers.
The best VoIP providers for business cost around $25 per month for unlimited calling. The best residential VoIP services cost around $10 a month for unlimited calling. Keep in mind: price alone is not a great determiner of quality.
Business and residential VoIP service plans are two different things. Residential VoIP plans are cheaper but that doesn’t mean your business should sign up for one. Business VoIP offers more practical features for an office. Typically, businesses make far more phone calls than residences, so the call limit is important. (VoIP providers try to protect their network from overuse, thus there is a "Fair Use Limit" to unlimited calling.)
Features for business VoIP include auto attendants and extension. There is also more variation between business VoIP plans. VoIP phone systems can be held on-site (IP PBX) with SIP trunking or by the provider with a system called hosted PBX. Or you can run your own phone system using wholesale VoIP.
Make sure you read reviews and research VoIP providers (We reccomend the reviews on our site and the VoIP reviews on voipreview.org).
A service that is convenient, helpful, and reliable is more valuable than the plan price tag. See how many reviews each company has and what reviewers say.
What plans do they offer? How do users like it?
Does customer service solve problems or blame the user?
Look for rates in international calling, offered features, and starting deals.
Once you know whether you need residential or business VoIP, decide how many minutes you need. There are unlimited plans (flat fee) or metered plans for a few cents per minute.
Read the terms and conditions of service. For example, residential VoIP providers rarely allow you to use their service for business purposes to protect the network from too much use and/or abuse of the system.