BTW, I don't think it's been mentioned in the thread or your initial post yet, but will you be taking payments via Paypal? If so have you factored in Paypal fees? Just in case you are not aware, depending on your account, you can be hit for anywhere between 2-4% for receving money, and 1-2% more for receiving international payments (fortunately for me, Canada is considered the same zone (domestic) as US). It might not seem like much until you go $50x50x4%. I wouldn't want you to lose money on the paypal fees for organizing this group buy.