Last year the time finally came for us to get an office phone instead of using my personal cell phone as the main office line. We didn’t want to actually get a land-line (so last decade), and we didn’t need a cell phone since it’s just for the office. After a few hours research we opted to get a Skype subscription with a Skype number (a few bucks a month) on an account that isn’t listed in Skype’s directory. We bought an older Android phone with wireless charging. This essentially gave us a cheap cordless phone for the office.
We bought a Nexus 4 from Swappa for $60. It doesn’t need cell service to be used with Skype; just connect it to your office wifi. It sits on my desk, and when it rings I can pick it up (or one of our devs since it isn’t “The Boss’s Cell”), handle the call, walk around the office, etc. We can also take calls on a computer if we want since it is a Skype number. This gives us flexibility for a very low initial and on-going cost.