In early high school, I dreamed up a scheme that I was going to build a 3D printer from cheap and salvaged materials. Of course, this would have been quite a long project, between the time it takes to accumulate materials, and then to design the whole thing. Unsuprisingly, I never got very far.
Eventually, I decided the solution was just to cave and buy a kit, which is what I did. Here's what I had to say about it at the time:
I didn't end up building a 3D printer from trash for $60. What actually happened is I bought a kit for like $150, which is pretty good for a 3D printer. I got the Anet A8, a Prusa-style printer made of laser-cut acrylic. It took me about a day to assemble. It prints PLA quite nicely. I haven't tested any other plastics yet, because I don't have them.
I set the printer up in my basment. I gave it a power switch (which it didn't come with originally) because I found it just slightly barbaric to plug and unplug the whole darn thing every time I wanted to use it. I aslo mounted a short length of LED strip to the underside of the control panel to illuminate the print bed.
For the sake of posterity, here is the link to to old 3D printer project page.