A:Answer I believe you’d have to buy into a plan before the expiration of the trail to use the the activated SIM card, Else you’d have to either purchase a card with the deal from a retail outlet or get it through Mint themselves at www.Mintmobile.com or (800) 683-7392. The key is to opt into a plan before the expiration of the SIM card. The bigger the plan, the better the savings. I just purchased the 3 month package because I was activating a new service on another phone. I’ve had Mint for 2 and a half years with their 12 month unlimited plan where I enjoy the biggest benefit. Service works anywhere T-MOBILE service works. Win, win situation.