Google has started trialling a same-day delivery service to rival Amazon Prime and eBay Now, called Google Shopping Express, in San Francisco. It’s a limited pilot for now, although anyone can register their interest in the service by filling out an online form here. Testers will be given a free six-month membership for unlimited same-day delivery with the following reputable brands and local retailers; Office Depot, Staples, American Eagle, Target, Walgreens, Toys “R” Us, Blue Bottle Coffee, Raley’s Nob Hill Food and Palo Alto Toy & Sport. Consumers will almost certainly need to pay for the service when Google gives it an official launch, but so far no details on this have emerged. Reports have suggested, however, that Google Shopping Express will be $10 or $15 cheaper than Amazon Prime, pegging it at roughly $69 or $64 for a 12-month subscription.