It seems that the first 15 days of a month usually have higher number of sales (~30% higher) than the last 15 days of the month. However, the amount per order is much higher (~40%) from the sales in last 15 days of the month. Monday tends to have a higher conversion rate and Saturday is the worse. I am guessing people are much richer at the beginning of the month because thats when most people get their paycheck and people don't usually browse the net on Saturday. I don't really have many months to base these number on. So I wonder if similar things happening to other sites?