Can I prevent an iPad app ever being updated? The latest version of Skype for the iPad has commercials. It will probably be necessary to upgrade at some point, but until then I want to stay with the commercial free version.

Is there any way I can prevent it ever being updated? I want to ensure that it will not be updated by accident.
Back up your iPad with iTunes. Back up that hard drive. Unplug that backup and store it far away from any internet connection. If you do update Sykpe by mistake, restore the iPad from the backup. It won't keep Skype from updating, but it will preserve your ability to undo the update.