Never...I really don't buy things off the internet.
I think I've join memberships to a couple of site for classmate or cards
and about a year ago, I purchased my system from a site my work orders from all the time.
www.pcusa.com
But that was nerve-racking...I really don't trust purchasing stuff where I can't get into their face if they fuck up.
Being scary looking when I'm angry has its benefits.