Sometimes you might luck out and get a buffet. The bread is not always fresh and the coffee might be reheated from the day before. Most hotels will assume that you are having breakfast at their hotel and will automatically add the extra charge to your bill. Let the front desk know whether you want breakfast. The only time you have no choice is if signs are posted on the wall stating that the room rate is the same whether you eat breakfast or not.
Breakfast is usually fresher, and cheaper , at the neighborhood 'bar'.
Price aside, I enjoy rubbing elbows with the locals standing up at the bar. Confirm whether the hotel takes credit cards or just cash. If they take credit cards, indicate that you want to pay by credit card, but ask if the price would be lower if paid by cash. A room with a shower and toilet is often cheaper than one with a bathtub and toilet, and a room without a shower or toilet is the cheapest. Make absolutely sure of what you are getting.