Automating tests is generally more expensive than manual testing in terms of initial setup and development costs. However, once automated tests are created, they can be run repeatedly with minimal additional cost. In contrast, manual testing typically requires human testers to perform the same tasks repeatedly, which can be more time-consuming and expensive in the long run.

It's worth noting that creating automated scripts for every manual test is not always the cheapest and best way to automate. Automating tests that are not frequently run or that do not provide much value in terms of detecting bugs or improving product quality may not be the best use of resources. Automated tests should be selected based on the goals of the testing and the expected return on investment.

Manual testers can run tests that an automated test would lack the context to interpret, and automated test script may not excel in interpreting the context of the testing. It depends on the scenario and the automation approach.