The $100 worth of trades can only be done through buy transactions going from Canadian Dollars to cryptocurrency. You can fund your account with at least $100 CAD via interac e-transfer or bank wire transfer, then use these dollars to buy cryptocurrency with dollars. A minimum of $100 CAD must be used in buy transactions is required in order to receive the referral bonus.
Purchasing cryptocurrency via credit card does not count towards the $100 worth of trading volume on Netcoins.