If you are looking for the most affordable rooms in the area of Apo Island, you will find them in Dumaguete city. The town has several hotels, many of them new, that offer basic rooms at very affordable prices. From here, you can take a tricycle every day to the dive resorts in Dauin (about 20 minutes).
In the city of Dumaguete you will also find some local restaurant with good and cheap fish and seafood. Ask your resort about places to eat in town.