Purchasing, as a major organizational function, is involved with a number of different types of budgets. These budgets include the purchasing department administration budget (also known as an expense budget), the production materials budget, and the maintenance, repair, and operating (MRO) budget. To use budgets wisely, you need to know how they work, what they are supposed to accomplish, and how they are constructed. In this lesson, you'll discover the primary purposes, advantages, and disadvantages of budgets. The lesson will cover how to select a budget period, review variable budgets, and understand budget variances.