Buying games from Canada in a US account. Cheaper?

I moved fork the States to Canada a few years ago. I've been using my Canadian account to buy content. I keep using my US account because of my nickname and the trophies.

I was checking the prices in pcgamesupply and I realized some games are cheaper if I buy pre paid card for the US store instead of buying in the Canadian store. I haven't buy anything in thay website so I was wondering.. Am I right? Is it cheaper?

If that's so. I'd stop using my Canadian account for buying I really miss using the cloud service.