The Dining Plan is part of the Residential Housing program and consists of 1800 Dining Dollars that are linked to your Campus ID Card at the beginning of the year (If you're staying one year, 600 Dining Dollars per quarter if you're staying less than one year). The funds may be used anytime at all UCSD Dining Services restaurants for meals, snacks, beverages, sundries, or groceries.
Each time you make a purchase, the amount is deducted from your account balance and the remaining balance is displayed on the cash register to help your budgeting. 1800 Dining Dollars mount to approximately 53 Dining Dollars per week. You can purchase extra Dining Dollars whenever you want, see the Dining Plan webpage for more info.
You can find a list of the 14 places where you can spend your Dining Dollars in the Dining Commons page. Everybody can use this facilities, even if they don't have a residential contract and then they don't have Dining Dollars. You can always pay by cash (no credit card accepted) and you may find it very useful as Dining Commons are conveniently located in all the six colleges.