It's easy to spend a lot more than the flat nightly rate at the average hotel, between the minibar, parking and who knows what else. Take advantage of the free amenities, like continental breakfast, and see if there are any deals to be had on the rest. For example, if you notice that the parking lot is full, ask the staff if they'll give you a discount on the daily rate.
Some hotels charge a "daily amenities fee" that covers a wide variety of services, like access to Wi-Fi, complimentary cocktails, printing and newspaper delivery. If your hotel charges a fee like this, be sure to ask for a list of the included amenities when you check in. That way, you can be sure to take full advantage of what you've already paid for.