Hi FTs,
6) How much does it cost for a taxi ride from YYZ airport to Markham city centre (about 40km)?
Try this:
http://www.a1airlinetaxi.ca/images/east.pdf
7) Whats the best data package from the operators/carriers (quota based/unlimited)?
If you need data, it's going to be expensive. If you can live with Wi-Fi and phone you can get a sim card for $10 for an unlocked phone and talk time at
http://www.speakout7eleven.ca/ They sell data plans for $10 a month for only 100 mb -it gets less expensive per unit if you buy more. This uses the Rogers GSM system.
Renting a car at locations other than the airport is always cheaper.