GST registration required or not.

Hello sir,Namaste,Mere papa comission basis pr bill discount krte hai? to kya unko gst registration lena hoga and rate kya hoga?commisiion 5-10% charge krte hai,cement company ke traf se unko current account m paisa aata hai and fir wo b usme se commision kaat ke aage bhej dete hai,suppose maine 100000 rupees kisi ko bheja to kya gst 100000 ke uper charge hoga ya jo hmne comission deduct kiya hai uske uper. TDS cut ke paisa aata hai.