PayPal is of the largest global payment gateway solutions. They operate in almost every country including Canada. It is easy to use and set up. PayPal has a very powerful API which can be used to customise the payments based on the merchants requirement.
Moneris Solutions charges the lowest transaction fee in Canada. If you're using Moneris payment gateway, you will have to pay a yearly maintenance fee of $143.4. For every successful transaction, you'll be paying 2% of thePayment Gateways (Canada)