For each trade they charge 1 cent per share where each trade is subject to a minimum charge of $4.95 and a maximum of $9.95. It does seem unusual from a first glance, but you shouldn't debate a good thing. This is incredibly low cost!
This kind of fee structure makes Questrade the ideal Canadian broker because no matter how many shares you trade you will never have to pay more than $9.95.
Questrade requires a minimum deposit for standard margin accounts. It's $1,000 minimum. To keep the account in good standing once open you only need to have $250 in equity (either via cash in the account or a combo of cash and stocks you own).
Their service is quite good and their pricing is unbelievable, and so is worth checking out if you are new to investing or even an active trader.