Hermit Scott, one of our regulars, had a long "engagement" discussion topic a while ago with a Humminbird (or Hummingbird - see spelling does matter after all for searches!) fishfinder with charts, but he's in Texas. I know they have them in Canada 'cuz I bought one for my father-in-law, but don't know about the more expensive models with the charts. They use in-hull transducers. So try the Humminbird website and look around and maybe make a phone call or two. Canadian Tire sells them. You could also do a search on this site for the brand name with the two spellings under author for hermit and find that discussion.
The other thing with less expensive models with charts: you get what you pay for - no kiddin'. I recall that the charts may only have been for a large area, hence, with less details than the average boater may want or need for a local area.
Do your homework and check it out if you're interested.
Other than that, checking the major manufacturer's websites will answer all your questions: Garmin, Furuno, Raymarine, Lowrance - check West Marine's or Defender's webpages if you don't have a catalog for all the different vendors.