You can buy dedicated Skype number for $6 per month. Please visit below Skype links:
http://www.skype.com/en/features/online-number/
http://support.skype.com/en/faq/FA256/how-do-i-set-up-my-skype-number
2. Unlimited US & Canada Calling Plan:
You can buy unlimited US and Canada Calling Plan for $2.99 per month. Please visit below Skype links:
http://www.skype.com/en/rates/
3. If you are using an Android Operation System, Download “Skype for Android” App for free from below Link OR you can download from your Android Apps in your Mobile Phone:
http://www.skype.com/en/download-skype/skype-for-android/
http://play.google.com/store/apps/details?id=com.skype.raider
4. If you are using an Apple iPhone, Download “Skype for iPhone” App for free from below Link OR you can download from your App Store in your Mobile Phone:
http://www.skype.com/en/download-skype/skype-for-iphone/
http://itunes.apple.com/app/skype/id304878510
Now you are all set for free and unlimited outgoing and incoming calls to United States and Canada