Sharing one printer with multiple computers is far and away one of the best uses for a local network. Instead of buying multiple printers, you can easily get by with one or two printers for a fairly large group of users.
One common way to share a printer is to use a network print spooler, which is a piece of hardware that connects printers to a network. The spooler accepts print jobs, and then spools the job to the selected printer. Print spoolers can be standalone or built into other devices, such as routers, NAS (Network Attached Storage), and access points.
But you don't have to buy a networking device to share a printer. You can share a printer by allowing others to access your computer and its attached printer.
To set up a shared printer system on your network without spending a dime, take a look at these printer sharing guides: