IF the LCD is physically cracked but the camera body otherwise works fine, then it might be worth taking the risk but unless this is the case AND you are capable of doing the repair yourself then follow Rick's sage advice and stay away from this "deal". There is huge variance in the selling price of used cameras in the public market so if you aren't in a huge rush, you are likely to find an equally good deal on a working camera without the risk of unknown repairs.
I have done many electronic repairs with gear ranging from 1930s tube type communications gear through modern SMD lab grade test gear and mil spec receivers. Modern equipment requires the proper tools (often hot air rework tools are needed for components including connectors) and with SMD there is a very narrow temperature window where proper solder flow occurs while safe component temperature is not exceeded. This requires both the proper tools and knowledge to use them and in a camera there is always a design need to make circuitry as compact as possible making any repair far more difficult. Depending upon your local climate, you will also need to be very careful not to damage other components with electrostatic discharge. It is winter in the midwest and I won't go into any modern gear without using a discharge device to keep those rapidly created static charges from taking out an expensive part of what you are trying to repair.
Rodger
EOS 1DX M3, 1DX M2, 1DX, 5DS R, M6 Mark II, 1D M2, EOS 650 (film), many lenses, XF400 video
