The way they charge depends on the category your connection falls in, iinm. I don't remember them cheating on the cost back when I'd used SOD; and you have the option to continue at the end of each hour, if you don't respond, sod is terminated and you're charged for the 1 hour you've used. Each session (1 hour) is 20 bucks ( 2mbps at night), even if you terminate it before an hour, you will be charged 20 bucks.