Discount for etransfer? OR surcharge for credit card payment?

How do I setup a surcharge to charge customers for using their credit card? In Canada we are allowed to charge up to 2.4%

A surcharge is a fee that a merchant may add to a transaction when a consumer pays by credit or debit card.Surcharges for credit card paymentsAs a merchant, you have the option of adding a surcharge to a credit card transaction (except in Quebec). Some payment card network operators (PCNOs) forbid surcharging for prepaid cards.
https://www.canada.ca/en/financial-consumer-agency/services/merchants/credit-fees-merchant.html

But is there a discount I can give for paying etransfer? Maybe that's the better message I want to give?

Here is how to do that:

https://www.ownerrez.com/support/articles/charging-guests-a-credit-card-fee

However, we do not generally recommend this, as guests find it to be a nuisance fee.

Thanks Ken! 

I've setup a 2% discount for etransfers and will see how many take advantage of that.