On my other ebay sight i have to have some pretty big boxes... I go to my local grocery store and get good quality large boxes from them.. lots of times i have to double box so they have to be lighter weight but strong.. and so far no one has complained that the boxes were from the grocery store.. Mainly because i choose clean boxes..
A large box can run up to 8.00 at office depot and my customers are glad i dont pass that price on buy using a similar sized grocery store box.