Thread note: split off from this topic about the documentation needed to buy t-shirts wholesale in the US
I don't know if you have all the info you need for this thread or not but I will share my two sense.
I'm in Ontario and what I've learned (specifically for American Apparel) is when they are asking you for your "vendor permit number" that "vendor permit" no longer exists.
A vendor permit number is now only an HST number. This is new. I had a hell of a time going around in circles until this was explained to me after calling Revenue Canada a few times to clear up the confusion.
Revenue Canada even has yet to update their website concerning the now obsolete vendor permit. There is a form to download to apply for one, but they will not process it because it no longer exists.
It's true that you don't need to get an HST number (GST and HST have combined and is now only HST) unless you bring in $30,000 a year or more. However, you can still get your HST number without earning $30,000 and you can use it for things such as wholesale accounts.
And of course your business number Once you register your business you will get one.
I hope this helps!