Medications are usually not too expensive in Canada because the prices are regulated. The pharmacists still make good money, just not quite as much as in the US. You may go to websites such as http://www.canadadrugs.com/ or http://www.canadapharmacy.com/ to get some ideas of prices. The prices on there are still higher than what I pay at my tiny neighbourhood pharmacy.
Many employers offer supplemental insurance that covers some of what your public healthcare doesnt such as medications, dental and vision care and some employers make you pay something around $40 a month for this coverage while they are paying also and so do not make you pay. If you don't have a job with supplemental insurance, you can buy it and it may cost you as little as $40 but you would not get very much coverage for that. More coverage cost more money. My employer makes me pay $40 a month and they pay another probably 80 for me and for that I get eyeglasses every 2 years, dental up to $5000 a year and 90% of medications.