More specifically, yes skype to landline costs money.
HOWEVER, if you are calling from North American to North America, its a flat rate of about 30 USD
per year. Long distance calls cost more, per minute.
So most calls, if you are a North American, are not charged "per call". I use it to talk to my boyfriend (hours and hours

), but at its current level of reliability and clarity, I wouldn't pay any more than 30 bucks a year. It works fine most of the time, but every now and then it doesn't, or call quality is crappy. So if you talk alot and a dropped call here and there isn't the end of the world, and you don't use it as your main line, just to cut down on costs, it works fine.