Sure, I use them from time to time in my lab to spin up test runs. I also have a cheap VPS ($25/year) that I do the same on. You could also use VMWare Workstation Pro (free) or Oracle Virtual Box (free), on your desktop/laptop, to spin up a Ubuntu or other server, and test to your heart’s content. I would think the 1 gb spec on the RPi 3 might limit you somewhat on what you could test run, but I have surprised myself as to what I can jam into an RPi 3. PiMyLifeUP has a ton of tutorials for the RPi. Might want to take a glance to see what’s possible, but, for an initial investment of $25 seems like a doable opportunity.