Have a look at the following website:http://garmin.openstreetmap.nl/
It is free, and gives you routable maps as good or even better than Garmin, that you can customize (i.e. choose province/country or select tiles) and update anytime you like.
The maps are based on OSM data.
The pre-selected maps (such as "Ontario") can be downloaded directly, whereas you will have to wait a little bit if you want to build a custom map with tiles of your choice.