AT&T has a new promotion offering double the data on its mid-range plan. For $40/month, customers get 16GB of high-speed data, instead of the usual 8GB. The plan also includes unlimited talk and text across North America. The promo requires that customers enroll in AutoPay (without AutoPay, the plan is $50/month and only includes the usual 8 GB of data.) The plan includes rollover, where unused data is available the following month. The promo works by adding a special 8 GB block of "bonus data" each month. That bonus data is used first, followed by the standard data allotment. The bonus data does not roll over. Therefore if a customer used 8 GB one month, they could have up to 24 GB of high-speed data available the following month (8 bonus + 8 standard + 8 rollover). The plan also includes HD video and mobile hotspot. The next plan up is the unlimited prepaid plan for $65/month ($55 with AutoPay), but that does not include HD video nor mobile hotspot. The double-data promo will be available until July 11th, but customers who sign up before then will continue to receive the double data as long as they stay on the plan and signed up for AutoPay.