Amazon.com launched a service Thursday that promises one-hour delivery of household merchandise to its Prime customers in Manhattan. The service is called Prime Now. Thousands of products like paper towels, shampoo, books, toys and batteries will get delivered within 60 minutes to select areas of Manhattan. This new service is available to customers enrolled in Amazon Prime, a membership service that costs $99 a year. One-hour delivery costs $7.99 but Amazon also offers two-hour delivery for free. Prime Now is available from 6 a.m. to midnight, seven days a week. It faces tough competition, however, from other delivery services in Manhattan, such as grocers FreshDirect and Instacart, as well as Google Express, which delivers for a variety of retailers the same day. Amazon wants to roll out one-hour delivery to more cities in 2015. It currently has 109 fulfillment centers around the world, more than 50 are in the U.S.