The area around San Diego is renowned for some of its luxurious resorts that generally provide accompanying golf course and tennis courts. These tend to have very high prices but they are superior properties with exceptional facilities.
There are plenty of Bed and Breakfast accommodation options in San Diego and there is the Bed and Breakfast Guide of San Diego who can help with sourcing this type of property.
If you are looking for a cheaper alternative, San Diego provides a number of hostels spread out between Downtown San Diego and the beachside neighborhoods.