The cost of food and groceries is an important element in any budget, especially if you are trying to save money. The best way to estimate your weekly or monthly cost of groceries is to simply save your receipts for a month and then average them out. This will give you a good estimate of what you spend. You just need to account for holidays and special occasions when they come around. Of course, it is important that you stick to your budget. When estimating what you spend on groceries, make sure you include any unscheduled trips to the store, or food purchased during work or on impulse. This is the best way to get an accurate estimate.