I have a Canada-US-Mexico plan with PublicMobile.ca, the few time I was down in NY before The Horrors, it worked well.
I think Koodo also have a similar plan, and FreedomMobile has a yearly plan that does the same.
You can have a basic plan for $20/month and they buy add-ons for roaming.
All in all, yup, it is expensive because Canada but they do work.
I actually thought of something else that might be a better option.
Have you considered using VoIP?
I use voip.ms, it charges 0.85/mo for the phone number, and I think 1 cent per minute, you can with your a voip app (they have their own) or just forwarded the calls to your US number.
It depends on how many calls you do, but I spend something like 25/year.
Good luck