Choosing a cheap stack

I'm a non-technical founder with design experience. I'm building [describe your app in 3-4 sentences, including what users do and what data it stores].

Recommend a stack, but justify it against MY constraints specifically:
- I'll be building with AI coding tools, so I need technologies that are extremely well represented in training data
- Budget under A$80/month until I have paying users
- I'm solo, so I can't afford to run infrastructure
- I need to be able to hand this to a contract developer later without them wincing

Give me:
1. Your recommendation, layer by layer, with one sentence of justification each
2. Where my particular app has a requirement that changes the usual answer
3. What I'd be giving up versus a more sophisticated choice
4. A realistic monthly cost at 0, 100 and 1,000 users, in Australian dollars — note which services bill in USD and assume a rate of about 1 USD = A$1.55
5. The one decision here that would be most painful to reverse later, and how to stay flexible on it

Help me design the database for [describe your app]. Don't write any code yet.

Interview me about what the app needs to store, then propose a schema. For each table, show me:
- What real-world thing it represents
- Its columns, their types, and which are required
- How it connects to other tables
- Who should be allowed to read and write each row

Then:
1. Draw the relationships as a simple text diagram
2. Explain it back to me in plain English, as if describing a filing system
3. Flag the three decisions here that would be most painful to change once I have real data
4. Tell me what I've probably forgotten — the fields people always wish they'd added from the start
5. Write the row level security policies alongside the tables, and explain what each one allows

Be specific about anything involving dates, times, money or timezones — I gather those cause the most pain.

I'm a non-technical founder building [describe your app] for the Australian market. It's a [Next.js / other] app using [Supabase / other] for data.

Compare hosting options for me — Vercel, Netlify, Cloudflare, Render, Railway, Fly.io — against my actual constraints:

- I will be charging users within a few months, so non-commercial free tiers are a trap
- My users are almost all in Australia, so latency to Sydney matters
- Some customers may ask where their data is physically stored
- I'm solo and non-technical, so I can't run servers
- I want predictable costs, not usage-based surprises

For each option tell me: what the free tier really allows, what I'd pay in AUD once commercial, which regions it can run in, how hard it would be to move away later, and how well it handles my specific framework.

Then recommend one, say what I'd be giving up, and tell me the one thing that would make you change your recommendation.

I'm about to commit to [stack]. Before I do, teach me enough to be dangerous.

For each part of the stack, explain in plain English:
1. What it does, and what would break if I removed it
2. Which files in my project belong to it
3. The three concepts I need to understand to not be lost
4. The most common beginner mistake, and how to spot it
5. Where the real documentation lives, and which section to actually read

Then give me a single mental model of how a request flows through the whole stack: user clicks a button → what happens, in order, until they see a result. Name the specific files in my project at each stage.