i went to toronto for spring break one year because i couldn't afford to go anywhere else
my wife (girlfriend at the time) stayed in a cheap hotel and then walked everywhere
hit up yonge street, the hockey hall of fame, gretsky's restaurant, the CN tower, some french restaurant near the theatre, the lion king and saw seinfeld perform live (wasn't on the menu, but she wanted to go to the eaton center to shop and a scalper stepped in front of us hawking tickets...i jumped on it right away because i didn't want to shop and the tickets were so incredibly cheap...i ended up sitting in a seat partially obstructed by a huge beam...)
if you can, get a buffalo or rochester entertainment book...everything we did in toronto (aside from seinfeld) was 50% off through entertainment book coupons