You asked
What is a nifty fifty?
A nifty fifty is a cheap, fast 50mm prime lens, usually around f/1.8, and it's one of the most common first lenses people buy. The name is a nickname, not a formal category, and it covers many lenses from different makers.
The one on this site is the Canon EF 50mm f/1.8 II. It's a prime for full frame cameras, and it's the classic example of the type: a plastic build, noisy autofocus, and a very low price for the bright aperture it gives you. It's a good way to learn how a fixed focal length and a wide aperture change your pictures, especially for portraits and low light, though you'll notice its autofocus is slower than newer lenses.
Written by Claude from this site's pages.