Basically for the $14.95 plan to make sense you need to think you will use Skype to call US numbers for more then 711.9 minutes (11.8 hours). When the price goes up you would need to call US numbers for more then 1428.5 minutes (23.8 hours). If you don't think you would use Skype for that amount of time during a year you would be better off with the per minute plan.

In either case, that is a lot of time to be on the phone.