Just know what you're buying.
You're buying a slow to focus, F8 telephoto lens, that requires all the ISO your 6D can muster to keep the shutter speed appropriate. For $70. If you just want to play around with 200mm, go for it. It's probably softer than some old 200mm pentax manual lenses that cost about the same. Simply fully manual. But with how slow this lens is with AF, you might as well do it with manual focus as you will not be doing much action with it.
It's cheap enough to not care, to try it out.
If you're wanting a real telephoto for full frame on a budget though, just look to some Tamron options. Great quality, VC, and reasonable prices. Otherwise, it's hard to beat a used 70-200 F4L at $450.
Very best,