My wife's sister & her family lived & worked in Toronto for a year, and we would Skype them most weekends. Only problem was my mother-in-law came over every Sunday to see & talk to her grandkids.
Didn't cost much, except for the initial phone call to set up the time to call.

The main problem was the time difference - 11am Sunday (Sydney) was 9.00pm Saturday night in Toronto, so at that stage the kids were tired & a bit ratty.
A friend of mine (a muso) recently moved to the West Coast of Canada (near Vancouver) and he regularly Skypes his brother here in Sydney. It seems to work well.