"... and you could find a used one for even less. ..."
I strongly discourage buying cheap lens, or third party lens, used unless you know it's past. At least be able to verify it is in good working and focusing order before.
A new nifty-fifty f1.8 is a 'reasonable' lens, however. Shortcomings noted!
EB
EOS 1DX and 1D Mk IV and less lenses then before!
