Thousands of Canadian retailers already have equipment in place to let customers pay for purchases with a swipe of their mobile phones, putting the country in the lead in developing a system that could one day make cash obsolete. If consumers embrace the system -- and that's still a big "if" -- clip-and-save coupons, transit passes, library cards and perhaps even driver's licenses could become things of the past. All that's needed is an agreement among banks, credit card companies and telecoms; it’s coming soon.