Strength of the part also depends on which way the layers are printed in relation to the part.

yes even more so with long/thin parts or parts that attach to things

would the parts it printed out be strong enough?

Kind of an open question  depends on what forces you are talking about compression strength shear strength or tension strength.
People are making prosthetic hands for kids from PLA they get quite the workout.

yes different materials will give different strength. High strength materials such as nylon will require more heat to process and likely beyond the limits of a low end hot end found on most printers You will need an all metal hot end such as an ED3 this is a $80 upgrade that you would need to install.
Price aside you need to figure out what features you need in a printer.
Things to consider.
print envelope what  is the max size part it will make.
power supply  amps/watts
Heat bed
Hot end
On board controls
Type of frame jungle gym , wood or metal cube. 
Looks is a clean neat appearance important.
Open  or closed source.  Does the manufacturer require you to purchase there filament , do you need to hack the machine to use open source material.
This is one to look at http://www.plasticscribbler.com/produc … terid-2000