Costco has a selection of acetate prescription frames for $180. They had Yardstick 3.0, Corkscrew and a few others. Oakley.ca lists these frames as discontinued with no pricing, and google shows pricing from GBP49 to US$268, so caveat emptor. Availability varies by frame but the yardstick 3.0 I looked at has 4 for all of Canada.