This is in Mississauga, while I'm waiting for the GO train
Currently in Mississauga, you need to use presto card for transportation fare, if you don't have one, you just need to pay 3.5cad per one way, its a little expensive (I think by 1cad). You can buy this to any bus station in Mississauga, there are some subway stations in Toronto where you can purchase the card.
The good news is, your bus fare ticket is still valid for 2hrs, so you can just hop on hop off to any bus as many as you want, LOL, just present you bus fare ticket or tap your presto card...the bad news, well you need more than 30mins to stroll, for example at the mall, especially if you're shopaholic, hehe
You can go to Mississauga from Toronto by TTC subway station, last stop would be Islington station, but from toronto downtown to center mississauga, will take approximately 2hrs. The fastest way is to ride the GO train, from union station to any point in Mississauga, and yes it is more expensive, hehe.. but it will only take you 30mins (big difference huh :D).