The screen repair for a N8 is about ~$279 in the US. If the crack on yours is insignificant don't worry about it. Instead, save that money for other things. The S Pen will function on a damaged screen, because it works on the principle of resonance.
Also, do not attempt DIY repairs on a N8. Disassembly requires a specialized machine that is not consumer-grade. Only trust Samsung or Ubreak with repairs.
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