38d00891_nced_Reports_Magento_Extension__Standard_kit_reports
[Application areas] Does it make sense to offer a 2+1 promo? What's a good threshold for quantity discount? [Standard kit reports] 
Products by Customer shows how many products are your customers buying at a time, e.g. “this week you have 2 orders of 4 items, 3 orders of 3 items, etc.”
Advanced Reports Magento Extension
Standard kit reports