How to burn 50k dollars trying to save a few hundreds
You are a brand new startup. No cash flows in at the moment. What are you trying to do? Survive. You are saving every single penny to last as long as possible. You stick with free tools, or stay with freemium plans. Are you really saving money by doing this?
How it happens
Once your startup launch is successful, you're growing fast and are rapidly acquiring new customers. As it grows, the tools you used at the beginning are less and less adapted to your changing needs.
You begin to look for alternative tools to complete the job. The open-source load testing tools hardly scales as the number of simulated users explode.