We travel through Antigua about twice a year. We host groups of engineers and students working on projects throughout the country. Usually our first night is in Antigua. It is about 45 minutes from the Guatemala City Airport and most in-country travel options are available.
Our student groups usually stay at the Black Cat Hostel which is just one block from the central plaza. The cost is about $8.00 per night to stay in a dorm style room with a shared bath. The water is hot and the place vibrates with energy. Fortunately they close the restaurant/bar at 10:00pm and the place calms down for the night.
The real treat at the Black Cat is that Breakfast is included in the price of your room - and it is a really great breakfast!
Check out: the Black Cat