On the main carriers, a 1GB data plan with unlimited Canada-wide calling is $100 after tax. (Occasionally, there will be a discount that all of the carriers do simultaneously where a few GB is added to each plan for free, and you can drive the price down a bit if you've been with them for a while and threaten to leave.)
Each of the big 3 carriers (Rogers, Bell, Telus) also has a "budget" subsidiary brand (Fido, Virgin, Koodo), where the same plan is $50 or $60. However, customer service is absolutely terrible and they ding you for absolutely everything. For example, if you ever need to call customer service, there's a $35 service charge.
This is for Ontario; other provinces have local carriers (Sasktel, Videotron, etc.), but I'm sure pricing is pretty much the same.
Oh, and roaming in the US costs an extra $10 per day to use your regular plan, even if you only send a single SMS. Best not to use it at all or get a local SIM if you're going to be there for a while.
Is that $100 CAD? If so, that's <$75 USD, which is more than we pay in the US, but not insanely so -- most people I know pay 50-60USD (not including any device payments).
