That's a reasonable proposition, but I think it comes down to your individual circumstances, frequency of need, and tolerance of inconvenience.

For people who have an office or home where a printer won't take up valuable space or look out of place, use it semi-frequently (let's say a few times per week or month), and might have to deal with the occasional urgent case, owning a $100 printer is a small price to pay to avoid having to spend an hour visiting the library (depending on distance of course) every time you need to perform 30 seconds worth of printing.

For a bit more money, you can get a multi-function printer with a built in duplex scanner and document feeder, which actually helps with running a paper-free environment. I have one of those sitting on my desk. Every piece of mail that arrives goes first into the scanner and then into the recycling bin, and avoiding trips to the library for printing is an added bonus.