Chaz Albert, a freshman at Mercy College in Dobbs Ferry, N.Y., is a passionate "texter," someone who loves to send and receive pithy text messages via cellphone. He does it at home, at school and at work. He often prefers texting over talking on his cellphone. Last month, though, Mr. Albert's habit caught up with him. Only $80 of his $400 cellphone charges were his father's, and most of his own, he said, were for text-messaging. "I was shocked, but I couldn't do anything about it," he said. "I didn't realize that I got charged for reading text messages. My...