The question is hilarious. You're basically asking us to tell you how to get rich quick. Let me ask you a fundamental question - would YOU be willing to give-up your house for 25% to 30% under market value? I thought you wouldn't. Now, ask yourself how many others are willing to do the same thing!!!! These things ain't easy to find.
There are a few ways of trying to find them - people who facing some sort of distress in their lives (death, divorce, job loss, family strife, moving, etc...). However, the circumstances have to be pretty incredible to part with that much money!! If the average house in Toronto is $400,000 a 25% reduction is $100,000 for a house that is in good condition. One thing you could do is offer CASH, thus avoiding banks on your part and giving them a cheque in hand, without having to go to their lawyer. You could also advertise that you buy houses quickly. I know people who have done this, and they can be somewhat successful at it - but you still have to know what you are doing.