Batangas is only 1-2 hours away from Metro Manila and has a lot of beaches - Anilao, Laiya, Nasugbu and Lobo. "Cheap" is a bit subjective for every person but you can check this site for recommendations: http://myresortsbatangas.com/
Morong, Bataan has beach resorts lined up and they can be rented for an affordable price. :)