Your main ongoing computer costs are probably for internet service and for ink for your printer.
As these costs come down you could very easily replace old devices with much better new ones and save money in the process.
The idea is to work out your cost for internet service and for ink. $30 can get you a new phone at very low-cost monthly rates from FreedomPop. $60 can get you a state of an unlocked BLU R1 phone which will work with the least cost providers.
Near WiFi you might not even need internet service.
Project these costs out against what you are paying now. It may be a no-brainer to add a new phone. With printers you can project the cost per page and achieve the same result.
Pretty soon you will have more smartphones and printers than you know what to do with! (Just kidding!)
What to do with the older devices? At the point where replacements are “break even” you don't need to get much out of them, and they will sell. They will be a bargain to someone else.
If you go the route of an unlocked smartphone, be prepared to be adept in snapping off the back and inserting SIM cards. YouTube videos will show you how.
Also be prepared to deal with almost unintelligible foreign phone voices when you need help.
But save hundreds and hundreds of dollars over time in the effort and move up to the latest equipment.