Going for a cheap display is the easiest option but that may ruin your smartphone quality and the original fit. The best option is to get it repaired or changed at Samsung Authorised Service Centre. They will provide you the Best fix for your smartphone.
Display and the Screen Glass are a 1 single component and not different. Even if the display is working, the entire Display needs to be changed if the screen is broken. There's no way of just changing the Screen Glass.