Allow your sales personnel to give price discounts to repeat customers (i.e. 2nd car the family has purchased, relative of a repeat customer is referred to your store, preferred customer discount on a replacement refrigerator (5th refrigerator in the family), etc.). To reward repeat customers, allow your sales personnel to give out bonuses or extras that will seal the deal with this repeat customer that your store would like to make happy. Give the salesman the ability to do this when it is warranted.