I did a poll on how often everyone made purchases but now I'm curious, how much do you average out each month in dollar amounts? If you buy each month just take the number average. If you buy twice a year etc add up and divide by twelve. So if you buy twice a year but spend $600 each time then 2 x $600 = $1200 / 12 = $100/m average. You don't have you grab your checkbooks and calculators. Just a best guess is fine!