Cloudant is a fully managed NoSQL database as a service (DBaaS), built on open source technologies and monitored, secured, scaled, and operated for you 24×7. Beyond the primary, technical-fit criteria for choosing a database management system (DBMS), cost of ownership is a consideration. What is more, many believe that the cost of fully managed services like Cloudant is expensive, relative to the cost of hosting and managing the DBMS oneself (DIY). This white paper compares the costs of using the Cloudant DBaaS versus another popular document-oriented database, MongoDB.