Most businesses with one to five people do not need a phone system. They need their existing number to ring them first, and something reliable to answer when they can't. That can be a cell phone, one setting at your carrier, and an answering layer behind it. A real phone system starts to make sense when several people share incoming calls, or when you need desk phones and a front desk.
The search results for this topic mostly rank systems against each other, and they assume you have already decided to buy one. This page starts one step earlier. It describes what each setup does, what it costs, and gives a table that matches headcount and call volume to the simplest thing that works.
What a phone system adds, and what it does not
A phone system gives you a few things a plain cell phone does not: several people ringing at once or in order, a menu ("press 1 for service"), call transfer, a shared voicemail box, desk phones, and call records. It does not, by itself, answer your calls when everyone is busy. A system with nobody at the phones sends callers to voicemail just like a cell phone does. People forget that, then buy hardware and still miss the calls.
So separate two jobs: routing calls to people, and making sure someone or something answers. The first job is what a phone system does. The second is what costs you customers when it fails. Our piece on how a one-person business stops missing calls goes deeper on the second.
Option 1: your cell phone plus forwarding
You keep the number you have. Your carrier forwards calls you don't answer, are busy for, or can't take to another number. It costs nothing extra on most plans, and you can switch it on or off with a code. For a solo owner or a pair of people who each have a cell, this is the entire phone system, and it is a respectable one. The limit is that it routes to one place. It cannot ring three people in order. The guide to forwarding your business number has the codes by carrier.
Option 2: a VoIP line
A VoIP line moves your calls onto the internet through an app or a hosted service. You get a business number, a shared voicemail, call recording on some plans, and the ability to ring several phones. Prices are per user per month. For a reference point, Google Voice's own page lists business plans at $10, $20 and $30 per user per month (as published on their site, October 2026), and its free personal version needs an existing mobile number and has no team features. Other hosted services price per user in a similar way; check each vendor's page for the current number. This fits two to six people who want one business number and a shared inbox. The cost is a login to manage and a number to port if you want to keep yours.
Option 3: a full phone system
A full system, hosted or the old kind with a box in a closet, adds an auto-attendant, queues, desk phones, extensions and reports. It is built for a front desk, a call team or several locations. The hosted versions are really VoIP with more features, priced per user. The on-premises kind is a purchase and installation project, and you should get a written quote before you decide it is worth it. For a team under about six, you will use perhaps a fifth of the features and pay for all of them.
Who answers when you can't
This is the part nobody prices, and it is the part that matters. When you are on a roof, in a client meeting or asleep, a call goes somewhere. The options are voicemail, a person (your own receptionist, or a service that charges for it), or an AI that answers. We wrote up what a receptionist actually costs if you are weighing a human. For the AI option, the answer to whether AI can answer your business phone covers what it does.
Rocketship's phone answering picks up on the number you already have through call forwarding, takes the caller's details and books a time on your calendar. The Launch plan includes 30 voice minutes a month. That is about 20 short calls, so size it by your missed calls rather than your total calls. If you miss 2 calls a day, that is about 44 a month. At around a minute and a half each, that is roughly 66 minutes, which fits the Frontier plan's 80 minutes, not Launch's 30. A dedicated phone number is not included on Launch or Frontier; a line is $5 a month. Mission Control includes 10.
The decision table by headcount and call volume
Match your row, then read across. The cost column assumes you keep your current cell plans.
| Team and calls | What fits | Extra cost |
|---|---|---|
| 1 person, under 10 calls a day, often on jobs | Cell phone, conditional forwarding, an answering layer behind it | $0 for forwarding, plus the answering layer |
| 2 people, 10 to 30 calls a day | Each cell forwards to the same answering layer; a second business number if you want to separate work from personal | Forwarding free; a Rocketship line is $5 a month |
| 3 to 5 people, 20 to 60 calls a day, calls shared | A VoIP line with a ring group, answering layer for overflow and after hours | Per user per month (Google Voice lists $10 to $30) |
| 6 or more, or a front desk, desk phones | Hosted phone system, answering layer for overflow and nights | Per user per month, plus desk phones if you want them |
| Several locations, call queues, reports | Hosted or on-site system with an auto-attendant | Quote needed |
Brennan Tile is a four-person crew. The owner, Luis, gets about 18 calls a day and answers about 14, so he misses 4 a day, roughly 88 a month. His phone system costs him nothing, and that is the problem. He does not need a new system. He needs conditional forwarding for the 4 he misses, plus a ring group if the two estimators want to share the line.
Switching without changing your number
There are two ways. You can forward the number you have to wherever it should ring, and leave it with your current carrier. Or you can port it, which transfers it to a new provider. Porting takes days, needs the account number and PIN from your current carrier, and is the step most likely to go wrong. Forwarding takes minutes and can be undone with one code. Start with forwarding, and port only if you are closing the old line. The iPhone forwarding steps and the options for a second business number cover both.
The phone is where a business wins or loses its next customer. Rocketship finds the buyers, emails them from your own Gmail, follows up, and books the meeting on its own, and it answers the number you already have so the calls that outreach creates are not missed. Plans that get you customers start at $24.99 a month (Launch), and both Launch and Frontier start with a 7-day free trial, card required. Answering your existing number is included; a dedicated line is $5 a month.