Odoo Odoo is an integrated suite of applications that includes modules for project management, billing, accounting, inventory management, manufacturing, and purchasing. Those modules can communicate with each other to efficiently and seamlessly exchange information. While ERP can be complex, Odoo makes it friendlier with a simple, almost spartan interface. The interface is reminiscent of Google Drive, with just the functions you need visible. You can give Odoo a try before you decide to sign up. Odoo is a web-based tool. Subscriptions to individual modules will set you back $20 (USD) a month for each one. You can also download it or grab the source code from GitHub. It's licensed under LGPLv3.