One of the frustrating aspects of using prompts to generate code is that the output can vary quite a bit even with the same prompt. Creating an API which use the OpenAI APIs for mission critical solutions feels a bit scary and unpredictable. For structured output, I know people use libraries like Pydantic with Python. I don't now the best approach to deal with this with regards to code generation, though. For now, I guess having an experienced software engineer examine the code is essential.
Increase the limit to something useful. Using your example of a contacts database, being limited to 100 records means I can't use your service to run my app for more than a month. Plus, as a side project it'd take me longer than that just to get it working.
Time limits put people off because you can't run a small project on the service, so any time you invest in learning it is going to be wasted if you can't/won't pay later on.
I actually really like IBM's Cloudant model where they change incrementally for everything but don't bill you if your usage for a month is under $50. That way I can happily build a small side project knowing it'll only cost me if it gets moderately big.
