Entering the World of 3D Printing

The Monoprice Select Mini 3D Printer (Item #153651) is their entry-level offering at $199. For an entry-level item, it has an impressive array of features. All the basics plus some not-so-basic features like a heated build bed. At the standard price it was already quite tempting. When Monoprice threw a 4th of July sale that cuts 20% off the price of any Monoprice-branded item... I could no longer resist.
As advertised, it came completely built and almost ready to go: the build bed levelling had to be double-checked because that can easily shift in transit, and indeed I had to make a few minor adjustments before it was level. It came with a micro-SD card with a G-code file ready to go, plus a short sample of PLA filament. I was up and printing within half an hour - very impressive!
The only complaint is that their sample filament is too short to actually complete the sample print job on the microSD card. If you look at the picture above (from Monoprice web site) it's in the middle of printing the same object, and it is stopped at around the same point as the filament running out. I'm not sure if that's a coincidence or intentional. In any case, I couldn't complete the print until I got more filament to feed the machine.
Now I'm learning all the basics of tweaking a 3D printer. Temperature, speed, all that good stuff. It also means I need to learn some new tools. A 3D design program (I'm looking at Onshape, but there are many others) and a slicer to turn the 3D design into a G-code file (Monoprice recommended Cura for this printer.)
My Ruby on Rails education has been seriously sidetracked by this adventure, but it'll be fun!