Advice to Implement Any Configuration Management Tool - Amazon Web Services

We have a particularly unique situation so I will try to be as clear as I can be.

Project information in Nutshell:

In one of my project we need to implement some configuration management tool (Chef,Puppet,Ansible etc). Project in Nutshell : We're supporting our client infrastructure which is completely running on AWS. They have five products which are being used by their clients. There setup is like this : 5 AWS Accounts(Prod in VA and CA Region, Dev (CA Region), Demo(CA Region), UAT(CA Region) these all are running in EC2- Classic. All the instance are running on Amazon Linux and each instance running multiple tomcats, each tomcat is hosting their different application which their client is using(Shared environment). These are customizable application based on client requirements. For each client they request us to setup a similar environment in DEV account. On the Front end we've Apache which is redirecting the requests to the respective application server based on it's vhost entry.

For their two other products we've setup a dedicated environment in VPC. In each VPC only that specific product is running. We've separated different schemas for each client using that product. Two applications servers running multiple tomcats+ One database server.

Till now they used to give us WAR file location. We used to download the war file and do manual deployments. Now, they requested us to set-up a Jenkins and they'll provide us access to a branch so that we've do the deployment using Jenkins.

Goal:

Client wants us to implement any configuration management tool. Although,after doing the architecture review I see less possibilities of reaping the benefits of CM tool in this environment because there are only two servers connected to one database server in all the environments. Don't see frequent changes in terms of provisioning more servers apart from deploying a new tomcat and setup a new environment for the new client, setup same environment in Dev account etc.

The Question:

Does anyone suggest a CM tool that can work best in the above mentioned scenario and how can it help? Also, suggest any cheap and best CM tool.

Thank you very much for the help :)