vercel or a $12 vps for an app router app at 300k requests a month Deploy

Been on a €4.50 box for 14 months with a Next app, Postgres and a worker. It is genuinely fine. The compose file is 30 lines, backups are a nightly pg_dump to object storage with a 14-day retention, and I have had one incident, which was me filling the disk with logs because I never set a rotation policy.

Set log rotation on day one. That is the whole warning.

Three things bite, in this order:

1. ISR cache is on local disk by default. One box, fine. The moment you run two containers for a zero-downtime deploy they each have their own cache and users see pages flip between two versions. You need a shared cache handler pointed at Redis, which is another service to run.
2. Image optimisation is CPU and disk. sharp will happily eat a whole vCPU resizing a 4000px phone photo, and the optimised images accumulate on disk until something fills up at 2am. Cap the sizes you allow and put a real cache in front.
3. You become the person who renews the certificate. Caddy makes that mostly automatic, which is why I use it over nginx for this exact setup.

None of it is hard. It is about two evenings up front and an hour a month afterwards. If that hour is worth more to you than $20, stay managed.

300k requests a month is 0.11 req/s average. That is nothing. Your decision is not about capacity, it is about which failure you would rather have: a surprise invoice or a surprise outage.

Before you move, go find the actual line items. In my experience the two that blow up small bills are image optimisation and middleware invocations, and both are fixable in place. I cut a bill by 70% by serving already-resized images from object storage and never touching the optimiser.

The honest cost is not the $12, it is that every framework major becomes your problem. Managed hosts absorb a lot of build-toolchain weirdness silently. On your own box you will read release notes.

I moved to a VPS to save $20 and spent the savings on a monitoring service so I would find out before my users did. Net zero, but I did learn a lot.

$40/month budget and 900 ISR pages - have you considered that 900 pages revalidating hourly is 21,600 regenerations a day for content that probably changes weekly? That is most of your compute right there regardless of where you host it.