Where to buy plain tshirts in Canada?

[casper_jj11]

I checked into the jiffy tshirt place and they don't ship to Canada. For those in Canada, where have you bought the plain tshirts in a variety of colours needed for transfers?

 

[TaliaB]

Zellers

 

[Zoebear]

Michael's
(sometimes they are on sale 2 for $6)