SAN FRANCISCO — Google Inc. plans today to introduce a long-anticipated payment system for Internet purchases as the search-engine giant attempts to enter every facet of online life.

Google Checkout will let shoppers save their credit card and shipping information through a Google account, then buy products from participating merchants, including Starbucks Coffee Co. and Buy.com Inc.

Industry analysts and Google rivals had expected Checkout to compete head-on against eBay Inc.'s PayPal, but the service is more similar to Amazon.com Inc.'s "1-Click" ordering system.

Google Chief Executive Eric Schmidt has often said Google searchers are only one click away from defecting to competing services. Storing their credit cards in Checkout ties them to the company more closely.