You can make a bunch of cool stuff for part mock ups or tiny little models. I have a Markerbot Replicator+ https://www.makerbot.com/3d-printers/replicator/
I use mine to print Warhammer 40K Armies to do test prints, or small car parts to test fit things and stuff. They can be VERY expensive and the print times can sometimes take hours, AND if you are fearful like I am, you can wake up and find a fucked up print that was scheduled to take hours. It's extremely frustrating to restart a print.
I love 3D printing, MicroCenter has a great selection at a reasonable price. Realistically, you could get into it for <$350 with a "good" printer. They make cheaper ones, but honestly... you get what you pay for IMO.