Amazon Web Services is bringing its pay-as-you-go billing to software as a service solutions on its marketplace. Users can now search for and buy SaaS directly from AWS Marketplace Vendors without monthly fees or subscriptions costs.

Usage charge for the services that users consume will appear on their AWS bill, according to a blog post by AWS’ Jeff Barr on Thursday.

A report last year by Pacific Quest found that 40 percent of SaaS companies use AWS to deliver their apps today.

“With AWS Marketplace SaaS Subscriptions you can access new products that weren’t available before on an AWS bill, easily search for and compare SaaS and API products on AWS Marketplace, and simplify your procurement and payment process with a single bill from AWS,” AWS said.

So far there are vendors in six main areas: application development and monitoring; security and log management; databases, BI, and big data; media; storage; other business applications and services.

AWS is appealing to ISVs who would like to offer an existing or new SaaS solution in the marketplace.