You can use real estate websites to find a rental property in Toronto listed on the multiple listing sites.
You visit Real Estate Rental Listings in Canada-houses, condos, land, property you can do searches for rentals. If your budget is $900, look at renting a room in a house or an apartment. The best source is Circlapp. You can search by area, price etc. However, give up hopes of finding an apartment for that amount.