This publication is intended to help you determine if you must pay California's sales and use taxes on your Internet sales. Download our free ecommerce terms and conditions template your online store and learn how to fill it out properly with examples.Learn which contracts are common to e-commerce businesses and how to manage high-volume transactions online. Minimize legal risk. In order to do business in the City of San Diego, a current Business Tax Certificate is required. Retailers engaged in business in California must register with the California Department of Tax and Fee Administration (CDTFA) and pay the state's sales tax. Use our Transfer Admission Planner to fill out your TAG application. If you have a community college counselor, review it with them. Congratulations on your offer of admission to San Diego State University! Out of the thousands of applications we received this year, you were selected!