Last July, as she has for the past 10 years, Dianne Jones spent 45 minutes on a city bus heading to the local WalMart.

There, under fluorescent lights, she scanned rows of brightly colored birthday cards to pick out the perfect greeting for her son—let’s call him Tim—who is imprisoned more than 100 miles from his mother’s home just outside New Orleans. The card she settled on was dark brown with trees and a birthday message that read, “For the best son in the world.”

Tim was in his 10th year of a 30-year prison sentence for an armed robbery he committed at age 17; he would not be able to see, let alone sit under or touch, a tree for the next 20 years. (Citing safety concerns, Jones asked that her son’s name not be used.) After Jones, her daughter, and her three grandchildren signed the card, she mailed it off, happy that Tim would know that his family was thinking of him.

To send a card to her son, who is imprisoned more than 100 miles away, Dianne Jones learned she would have to use JPay. Akasha Rabut

Days later, the card was returned. Puzzled, she called the prison where she learned the facility had instituted a prohibition on greeting cards. If she wanted to send a card, a prison official told her, Jones would have to pass along her greeting electronically using JPay, a company bringing email into prison systems across the nation.

Prisons are notoriously low-tech places. But urged on by privately owned companies, like JPay, facilities across the country are adding e-messaging, a rudimentary form of email that remains disconnected from the larger web. Nearly half of all state prison systems now have some form of e-messaging: JPay’s services are available to prisoners in 20 states, including Louisiana.

On the surface, e-messaging seems like an easy and efficient way for families to keep in touch—a quicker 21st century version of pen-and-paper mail. Companies like JPay cover the price of installing the systems; prisons pay nothing. And, the argument goes, closer family connections are a win-win for prisons and inmates. “Maintaining a positive network of support is really important to their future success when they rejoin the community,” says Holly Kramer, a communications representative for the Michigan Department of Corrections, which has contracted with JPay since February 2009. “Electronic messaging can help facilitate that.”

In the outside world there are numerous companies offering free email accounts—Gmail, Yahoo Mail, Mail.com—but inside prisons companies charge a fee, a token JPay calls a “stamp,” to send each message. Each “stamp” covers only one page of writing. Want to send photos of a nephew’s graduation, a niece’s prom dress or a new baby? Each picture costs an additional stamp. A short video clip? That’ll be three stamps. With the postal service, stamp prices are fixed, but JPay’s stamp prices fluctuate. Shortly before Mother’s Day, for instance, a stamp cost 35 cents; the price rose to 47 cents the following week. For a few hundred dollars, prisoners can skip kiosk lines by buying a tablet—a relatively expensive purchase that tends to lock them into JPay’s services.