I got my alignment done for both back & front for a total of $65 which included rotating tyres front to back & visa versa. They provided a detailed before/after measure as an FYI.

They do recommend an alignment every 5,000-10,000 klms depending on your driving etc. Mine is driven 100% on made road so I'll do it every 10,000 klms & see how I go next time to determine how far out it was.