When you buy a device on a plan, the cost of the device is divided by the number of months you choose to pay it back in (12, 24 or 36) so the answer is no, you won't end up paying more than if you buy it outright. However, when you buy a device on a plan from one of the major telcos, the plans that you can choose from are generally more expensive than similar ones from smaller telcos. So in that sense, you will probably end up paying more for the phone service, especially if you opt for a 36-month plan because you are locked in for three whole years.