Build Your Own 'Notion AI' for $1/month: Notion API + OpenAI in 50 Lines

I was paying $20/month for ChatGPT Plus and considering Notion AI Business ($20/user/month) to get the workspace-aware AI features. Then I did the math: Notion's API is free, OpenAI's gpt-4o-mini is $0.15 per million input tokens, and my actual usage is ~5,000 input tokens per query. That's $0.00075 per "ask your notes" call. Even at 100 queries a month, I'd spend less than a dollar in API costs. This is the build-vs-buy take the SaaS comparison sites won't write. Below is the 50-line implement...