Tucked away on the East Mall, back from the street, on the second floor - do they want anyone to find it? - is the McGregor Socks Outlet in Etobicoke. I have gone a few times and are always pleasantly surprised by the selection and pricing.
They have men's undershirts and underwear, along with a variety of socks from thick and warm to dressy and corporate. McGregor brands include "Happy Feet" "Calvin Klein" and "American Esssentials."
Lots of selection for the ladies as well, socks, leggings and I believe some tights. Pricing seems to start at about 25% off, with various things being put on deeper discounts for a week at a time. I'm usually the only person there, and it always has the feeling that it could disappear at any time, so check it out before it's gone!