1) THE CHEAPEST
The cheapest way to make and receive phone calls is with GoogleVoice, which is one of the services provided by the search engine company Google. They will assign you a free telephone number and let you make free calls to the US and Canada and receive calls from anywhere all for free. You can call home phones, businesses, cell phones and so on. Non U.S. numbers are relatively cheap to call, but you may find cheaper alternatives to GoogleVoice for international calls. Still, their international rates are not a bad price, just not the cheapest.
GoogleVoice has voicemail, voicemail to email, call screening, call blocking, groupings of people, limited call treatments, time of day treatments and ring groups which allow you to have multiple phones ring and the first to answer gets the call. You can also then transfer that call back to the ring group to have someone else answer. All-in-all, not bad for free.
You can configure GoogleVoice to allow you to call into your own number, enter a password and make a call using GoogleVoice. Google places the outbound call for you (free) and connects it to the call you are on. If you use the web-based system, you login to GoogleVoice, click to place a call and decide which number you are at, and which number you want to call. Google places both calls and links them together, thus both of you get an inbound call.
If you wish to use a regular telephone and GoogleVoice as a complete system, there is hardware from ObiHai which does that. To my knowledge, Obi devices are the only devices that work directly with GoogleVoice. You conect an adapter to your phone and the internet, then pick up the attached phone, receive a dialtone and dial away, simulating a traditional telephone company service.
GoogleVoice also has an option where you can place an icon on a website where people can click to call you. They don’t see the number being dialed and they can hide their own number from you. This might be used if you want to sell something on Craigslist or Ebay, etc.
There is no 911 service available and you would have to either use a non-emergency number or other 911 service.
Google does not have a presence in some states or rate centers, thus you may not be able to get a phone number in your area. In that case, choose an area elsewhere or find a place where you want to have a local number (maybe where you have relatives) who can call a local number to reach you for free.
You cannot easily port a home telephone number to them, just cell phone numbers. Some people have successfully ported a home phone number to a throwaway cell phone, then, ported that number to Google. It is not guaranteed that this will work.
Some people have had problems using GoogleVoice to call certain toll-free numbers. There are free services that allow you call toll free numbers, so you would configure them as a provider and just forward any toll-free number to them instead of GoogleVoice.
NOTE: 5/18/2014: Google Voice services which *used* to be accessed with Google Chat are being moved into Google Hangouts.
FURTHER NOTE: Although you can use GoogleVoice with an Obi adapter, I would suggest that if you are not a real techie type of person, that you use a regular Voip supplier instead. That will end up costing you a few dollars a month but may eliminate lots of “gotchas”.
2) OTHER VOIP SERVICES
Now we drop down to other services, not necessarily free.
If a GoogleVoice number is not available, companies like Voip.MS have numbers available for many locations. Their rates vary depending upon the type of service you want.
They offer a cheap monthly rate for the phone number with a pay-as-you-go rate of $1 a month for the number and a penny a minute for inbound our outbound calls.
Or, you could choose to pay $5 a month and get 3500 inbound minutes free. You would still pay a penny a minute outbound. Unless you get lots of calls, the cheaper plan may be a better choice. You can change plans at any time.
There are other companies, which operate similarly, and some offer a flat rate for a particular number of minutes of calls in or outbound. Broadvoice charges one rate if you have your own device. There is a rate for only calls out to people in your state, a rate for US only and another for International. They all carry a particular number of minutes in the plan. There may also be FCC charges and other charges added in, so you must read all documents about how you will be charged.
So what charges for calls might you pay?
I wish there was an easy answer but this is like saying “What is the cost to go from New York to Miami?” Do you own a car, does it use gas or electric or diesel? Are you flying or taking a bus or ride sharing?
Generally, GoogleVoice offers free telephone numbers in the U.S. and free calling to the U.S. and Canada. The telephone number may be in your city or state but not guaranteed. All inbound calls are free.
Other services found under VOIP providers vary a lot. They may split inbound and outbound calls and may have different rates. Still, their charges are reasonable if you make a reasonable number of calls.
If you port an existing number to them (let them hold your phone number on your behalf), that port may be free or you may get a small charge to transfer the number to their service. You may then pay them a dollar a month to hold that number in your account.
You may expect to pay a penny or less per minute for calls. Some services offer cheaper International calling than domestic calling. Alaska and Hawaii may be a bit higher than a penny a minute.
It used to be that the phone company (Ma Bell) charged per minute rounded up to the next minute. at $1.00 a minute a call lasting 61 seconds might cost $2. Most Voip services charge in fragments of a minute. For example, Voip.Ms charges in 6 second increments. 1 minute and 1 second would cost 1.1 cents. (a penny a minute plus 1/10 of another penny). My calls to the U.K. cost 7/10’s of a cent per minute so an hour to the U.K. costs perhaps 42 cents.
The services often come with free extras like voice mail and call blocking, etc. You may be able to get fax to email service where they answer with a fax tone and convert a fax to a PDF and mail it to you.
Oftentimes, the free extra services can add so much value to your service that a slightly higher cost per call can be offset by perhaps the ability to block hundreds of different telemarketer numbers for free.
There may be a slight cost for optional 911 services.