Please check my grammer and sentences

Suddenly i found a old CDMA DATA card in my dirty room with R-UIM card. Then i decided that used it to surf internet in high cost and high speed. Then i get out from my room and go forward for searching recharge card, while searching in the road i saw a old man is sitting backward of his shop, then i asked for him to give a recharge card of NRS.500. I buy and move back to my home and i recharged my R-UIM card. After that i decided to check my grammer and sentences and now i am here.