A monetary account, such as a prepaid account or credit account, that is used as payment for purchases is divided into categories of purchased items. When a purchase is attempted, a request to apply the monetary account specifies the category of the item being purchased. Rules associated with each of the categories of the account are applied in response to the request to determine whether to approve or deny the purchase. Rules may vary from one category to the next. As one example, a rule may include a remaining monetary value of the category where a determination is made whether the cost of the item being purchased is no more than the remaining monetary value. As another example, a rule may include whether a time of the purchase matches an allowable time for the category of the item being purchased. Other examples include rules that allow for borrowing from one category for purchases from another, for specific allocations, and for event triggers to generate alarms.