1 Depending on the cell phone carrier, most SIM cards are going to cost anywhere from $1 to as much as $35. 2  For instance, the AT&T 3G SIM card that is unactivated retails for $2 to $5 online, while the T-Mobile USA SIM card with the prepaid activation kit can retail for $6 to $10. In a forum thread on AT&T’s main support forum, a customer noted that he was charged $25 for a new SIM card after his previous phone was stolen. 2  PinShack.com has a similar forum thread where users discussed receiving a new SIM card. 3  Users here stated that the card could range anywhere from free to as much as $25 or so.