What's the cheapest database for a side project?
Choose the database your app needs, then check compute, storage, idle behavior, overage controls, and restore options. Free and paid entry plans belong in separate columns.
A database can cost nothing to start and still be the wrong choice for a project. Begin with its data model, queries, durability requirements, and hosting environment. Then compare a small workload across suitable engines. An empty database's sticker price tells you little about backups, growth, or the first busy month.
Choose an engine before a promotion
- PostgreSQL: evaluate providers such as Supabase and Neon if your application expects Postgres features and drivers.
- SQL Server compatibility: evaluate Azure SQL when those capabilities are part of your application or learning goal.
- SQLite: evaluate a local database file for a suitable single-host application, or a managed service such as D1 when it matches the deployment platform.
- Other engines: retain an existing dependency when replacing it would require substantial application changes. A cheaper database is not a saving if migration becomes the project.
A .NET application can use more than one engine. Choose Azure SQL because it fits the requirements, not because using .NET automatically requires SQL Server. Likewise, an autonomous Oracle database is not a PostgreSQL service simply because both accept SQL.
Free plans and paid entry plans
| Option | Starting offer | Important distinction |
|---|---|---|
| Supabase | Free plan with included usage | Postgres plus additional backend services; database size, file storage, and egress have separate allowances |
| Neon | Free Postgres plan with quotas | Scale-to-zero affects idle behavior; compute, storage, and transfer limits are distinct |
| Azure SQL Database | Eligible free offer | Select the offer explicitly and choose what happens at the limit |
| Cloudflare D1 | Free plan with usage limits | SQLite-based service; reads, writes, and storage are separate dimensions |
| PlanetScale | Paid entry options | Offers Postgres and Vitess/MySQL; do not list it as a universal free hobby database |
Supabase's Free plan currently lists a 500 MB database allowance. That is different from its file-storage allowance. Neon also publishes separate free-plan quotas rather than an unlimited database. PlanetScale currently advertises a single-node Postgres entry option from $5 per month; the product and deployment choice matter.
These facts help form a shortlist. They are not a complete price quote. Read the current plan page, select a region and deployment type, and include any required paid features before deciding.
What happens when the limit is reached?
The answer is provider- and plan-specific. Do not assume every free tier fails safely before a bill, or every paid tier has a spending cap. For each candidate, record whether a limit suspends service, rejects operations, requires an upgrade, or permits additional billable usage.
Azure SQL's free offer provides a choice between pausing until the next month and continuing with additional charges. Choosing the additional-charges option cannot be reversed back to the free-offer pause option. Read that selection carefully when creating the database; a budget alert does not replace it.
D1's Free plan has daily read/write limits and storage limits. Paid-plan billing has its own model. Estimate the rows processed by your queries, not just the number of API requests. An unindexed query can scan more data than its small result suggests.
Idle behavior is an application requirement
Neon can suspend idle compute and wake it when needed. Supabase's Free plan can pause an inactive project. These are different behaviors: a waking compute service and a project that needs resuming should not be described as the same cold start.
Test the first request after an idle period with the actual plan. Measure the user-visible response and confirm the client's timeout and retry behavior. If the application must be immediately available, compare a suitable paid plan rather than trying to keep a free service awake artificially.
A practical comparison worksheet
- Describe the data. Record expected database size, indexes, file uploads, growth, and how long deleted data remains in backups.
- Describe the queries. List common reads and writes, concurrent connections, background jobs, and expensive reports.
- Record the plan controls. Write down included usage, overage behavior, idle behavior, and notification recipients.
- Test recovery. Export representative data and restore it into a disposable environment. Check schema, row counts, constraints, and application queries.
- Price a busier month. Compare normal traffic, a realistic increase, and a configuration after the introductory offer ends.
Keep the worksheet beside your deployment instructions. Record measured usage separately from a calculator estimate. A trial with tiny seed data does not establish the cost of a production dataset.
When a local SQLite file is enough
For a suitable single-host application, an embedded SQLite database can simplify the architecture. You still pay for its host and storage and must handle backups, persistence, and concurrency. An ephemeral server filesystem is not a safe place for the only durable copy of the database.
Choose a managed database when the application needs its capabilities or when administering a database is part of the learning goal. If you later change engines, test migrations, data types, and query behavior; portable SQL is not the same as identical behavior.
Keep a side project small and honest
Limit retained test data, inspect indexes, and remove unused preview databases. Never copy sensitive production data into a public learning environment. Practice connections and secret handling in Class 9 and cost analysis in Class 32.
Common questions
Are all providers in this comparison free?
No. Free plans and paid entry options are separated. Check the plan and required features before creating the database.
Does every free database stop before charging?
No universal rule applies. Read the selected plan's overage behavior and any setting that allows additional charges.
Is SQLite really free to run?
The engine can avoid a separate managed database bill, but its host, storage, backups, and operations still have costs.
Sources and review
Reviewed 1 October 2026. Provider offers and limit behavior were checked against primary sources. No database benchmark or measured monthly bill was produced for this comparison.
- Supabase pricing and plan limits
- Neon Free plan limits — official documentation source
- Neon scale-to-zero — official documentation source
- Azure SQL free offer and limit behavior
- Cloudflare D1 pricing
- PlanetScale plans
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