have you tried installing Root Checker to determine if it's not already rooted? i got two bargain bin models which were rooted out of the box!
Samsung Galaxy S3 (Stock, rooted TouchWiz)
Samsung Galaxy Tab 3 7.0 (non-rooted, stock)
Samsung Galaxy Tab 2 10.1 (obsolete, slow, rooted)
Samsung Galaxy Note 10.1 2014 Edition