Ok well there are options. But first you need to find out which screen is broken.
The phone has "3" screens. A digitizer (the thing that registers touches), a LCD (thing that gives picture and finally the glass (Sits right at the front to protect the other 2).
If the LCD and digitizer are both working fully and it is only the glass the repair should actually be very cheap. You can even buy just the glass for like R100 and do it yourself but it is very tricky and dangerous if you are not tech savy.
If the digitizer is broken as well the repair could be a few hundred. If the LCD is broken as well the repair is normally about R1600 and up. You can get cheap screen assemblies containing all 3 screens for about R1400 off bidorbuy and do it yourself. This process is fairly easy if you are technically minded and have the tools.
If it is just the glass you can perhaps ask Samsung for a price, it should be under R300 i would think and they can do it better then you can
You can try Procell as well, phone them and tell them which part is broken and needs replacing. If its the LCD it will still be very expensive.