Mailing invitations to Canada

I was just about to start putting together my FH's family's invitations and his mom dropped the bomb on me at the last minute that it costs more to mail things to Canada. Could you imagine the horror of receiving back a bunch of invites, having to disassemble them, re-order envelopes and re-stamp everything? It's going to cost $2.20 per invite between the invitation and response card. Anyone have experience with addressing invites to Canadian addresses? Formatting help needed.