Amazon Simple Storage Service
Developer Guide (API Version 2006-03-01)

Amazon S3 Bucket Limitation

Each of your customers can have up to 100 buckets for each Amazon DevPay product that you sell. For example, if a customer uses three of your products, the customer can have up to 300 buckets (100 * 3) plus any buckets outside of your Amazon DevPay products (i.e., buckets in Amazon DevPay products from other developers and the customer's personal AWS account).

If your customers require more than 100 buckets in an account, they can submit a bucket limit increase request. For information about how to increase your bucket limit, go to AWS Service Limits in the AWS General Reference.