IMHO All loose teas are not created equal. Yes, you can purchase in your grocery stores, but again IMHO, they are usually no where near the quality. To me, hardly worth buying! I have bought loose teas from many shops that promote themselves as being specialty tea dealers, and many times been disappointed.
The best by far ...
http://www.davidstea.com/
They have shops across Canada and USA. You can order online and have it shipped direct to you.
It may seem costly ... the enjoyment is well worth it!!
As a hint ... if you're on the go, look for a bodum press style travel mug. David's sell them ... I use on that I got in Starbucks. And for the convenience, I have found that I use it for myself at home more so than brewing in a tea pot!