Honestly, you will seldom find a full furnished condo in Scarborough region. There are some available in Toronto area, specially at/near downtown. The price varies from $1600 to $2500 for 1-bed. However, these buildings are medium to upscale that come with underground parking, secured facility, gym/pool, concierge etc. Most apartment buildings are managed and rented by property management companies and hence they are not furnished. Furnished condos (privately owned) are partly/fully rented on shorter terms.
If you need to stay in Scarborough, then it's better to rent an apartment and gradually buy furniture.
If you ought to have a furnished condo, then your safest bet would be Scarborough basements or Toronto / North York / Mississauga area.