Every "how much does it cost to build an app with AI" question I get is really two questions wearing a trenchcoat. There's the cost of getting the thing built — which on most platforms, including this one, is close to nothing for a simple site. And then there's the cost of keeping it alive: hosting, a database if you need one, whatever third-party APIs your app calls, a domain, and the traffic you hopefully get. That second bill is the one that surprises people, because nobody itemizes it before you hit publish. So here's the itemization.
Is my site actually free to host forever?
If it's static — marketing pages, a portfolio, a landing page with a contact form, most of what the builder produces on a first prompt — yes, close enough to forever that it doesn't matter. Static assets served off a CDN cost fractions of a cent per visitor, and a free tier absorbs that at any traffic level a new site is going to see for the first year. The catch isn't the hosting, it's what people mean by "static." A blog with a comment section isn't static. A dashboard that logs in users isn't static. The moment your app needs to remember something between visits, you've left the free-forever category, even if the pages themselves still look like plain HTML.
What happens when my app needs a database, not just pages?
This is the real fork in the road. A database means a running process somewhere, and running processes cost money whether anyone's using them or not — that's the difference between a CDN bill and a compute bill. Budget for it like this:
| What you're running | Typical monthly cost | When it applies |
|---|---|---|
| Static site, CDN only | $0 | Marketing pages, portfolios, landing pages, most first builds |
| Small managed database (Postgres/SQLite-on-disk) | $0–$15 | User accounts, a waitlist, a simple CRUD app under ~10k rows |
| Managed database at real scale | $25–$150+ | Thousands of active users, background jobs, anything with write-heavy traffic |
| File/object storage (images, uploads) | $0–$10 | Any app that lets users upload something |
The free-tier trap is that the $0 rows are genuinely free for a long time, so people extrapolate that flatness forward and get blindsided when row two arrives. It doesn't creep — it's a step function. You're at $0 until you add auth or a form that writes to a table, and then you're paying for a server that's on 24/7 regardless of whether it's serving one visitor or a thousand.
Do AI API calls inside my own app cost me anything extra?
Yes, and this is the one builders most consistently forget to price in. If you ask the AI builder to build you a site, that's a build cost, handled by credits. If the site itself calls an AI model at runtime — a support chatbot, an image generator, a "summarize this" button — every one of those calls is a live API request that costs money per use, paid to whichever model provider you've wired up, every single time a visitor clicks it. A build-time cost is one-time. A runtime AI feature is a recurring cost that scales with your traffic, and it's the fastest way to turn a viral moment into a bill you didn't expect.
The fix isn't to avoid AI features, it's to cache aggressively (don't regenerate the same summary twice), set a usage cap, and know your per-call cost before the feature goes live rather than discovering it in an invoice.
What's the single biggest cost surprise builders hit in month two?
The database step function above, by a wide margin. Second place is a runtime AI feature nobody rate-limited. Third — and this one's almost funny in hindsight — is forgetting the domain renewal. You paid $12 for a year, felt done with money, and eleven months later a registrar email goes to a folder you don't check. The site doesn't go down gracefully; it just starts resolving to a parking page one Tuesday, and you find out from a customer, not from your own dashboard.
Should I budget for a domain, or is that included?
Domains are a separate purchase from whoever you register through — typically $10 to $20 a year for a `.com`, more for shorter or newer TLDs, and that's a cost you'll pay regardless of which builder or host you use, because it's paid to the registrar, not the platform. Treat it as the one line item that's genuinely fixed and boring: pick a registrar, turn on auto-renew, and forget about it on purpose.
What happens when traffic spikes — do I get a surprise bill?
Depends entirely on what kind of spike. A static page getting hugged by Hacker News is close to a non-event on a CDN — that's precisely the traffic pattern CDNs are built to absorb, and the cost per additional visitor is negligible. A spike that hits a database or a runtime AI feature is a different animal, because now every extra visitor is an extra query or an extra model call, and those don't get cheaper at volume the way CDN bandwidth does. If your app has both a static marketing page and a logged-in, database-backed product behind it, the marketing page can go viral for free while the product page underneath quietly racks up compute cost per signup. Check which parts of your app are static and which aren't before you assume "going viral" is free.
When does it actually make sense to move off the free plan?
Roughly: the moment your app needs to remember a user between two visits. Not before. I've watched people upgrade preemptively "to be safe" for a static portfolio that will never need more than the free tier offers, and separately watched people stay on free tiers for weeks after their app clearly needed persistent storage, held up by scripts and workarounds that cost more in engineering time than the upgrade would have cost in dollars. The free tier is generous for what it's built for — pages, not state. Once you're storing anything, price out the smallest paid tier honestly rather than treating the upgrade as a failure.
A founder I talked to described her first month like this: "The build was free, the hosting was free, and then I added a login page and suddenly I had a bill. I didn't do anything expensive. I just added a database." That's not a bug in how any of this is priced — it's just where the free part of the internet actually ends.
So what's the realistic total for a small, real app?
For a static site: $0 to host, ~$12/year for the domain, done. For a small product with logins and a database, low but real traffic: figure $0–$15/month for the database, $0–$10 for storage if you handle uploads, plus whatever runtime AI calls you've wired in — often the largest and most variable line if you have them, often zero if you don't. Add the domain. You can run a genuine small SaaS for under $30 a month for a long time before growth forces the next tier. The number that should worry you isn't the total — it's which of these lines scales with usage and which doesn't, because that's the one that decides what happens to your bill the day something you built actually works.
