Why is a return flight cheaper than 1 way?

[lilyfrog]

Hiya,

I am moving to New York in January and I was wondering why it costs almost twice as much to fly 1 way as it does a return flight, and would there be any repercussions in buying a return flight and just not returning?

Thanks

[JoolsTwo]

I don't know why - but my daughter got a return when she emigrated to Canada and didn't use the return half as it worked out cheaper that way. So no repercussions.