The "Cassandra Total Cost of Ownership Study" reveals that serverless Cassandra is significantly less expensive than self-managed OSS Cassandra, with a cost difference of $740,087 versus $3,174,938 over three years. The study includes dedicated compute hardware, cost per read and write operation, storage growth, and people costs in the TCO calculations. It also establishes a realistic performance test using NoSQLBench for serverless Cassandra pricing and determines the configuration of the OSS platform. The results show that serverless Cassandra is 75% less expensive than self-managed Cassandra, with 95% fewer production costs, 3x less complexity, and 44% lower operational costs. This test validates the immense value of serverless Cassandra for a Cassandra deployment in an enterprise project, offering significant reduction in deployment time and costs over self-managed Cassandra workloads.