It starts about cutting costs by the choice of infrastructure and goes further to less resource hungry tools and cheaper services. But never compares the cost of these things. Do I save actually the upgrade to a bigger server by using Go and sqlite over let's say Python and postgres? Or does it not even matter when you have just n many users. Then I do not understand why at one point the convenience of using OpenRouter is preferred over managing multiple API keys, when that should be cheaper and a cost point that could increase faster than your infrastructure costs.
There are some more points, but I do not want to write a long comment.