Spreadsheet is always a good start. Simple , free and works on a small scale. As you overgrow it, you will know why it is not working anymore and that will help you to find a tool that does what your spreadsheet stopped being able to do.
1. Start with simple, readily available tools.
2. If you outgrow those: Buy an off-the-shelf product.
3. If you also outgrow those, only then consider building your own solution.
If it's not a key differentiator for your business then you're probably better off with not overthinking it and going for the simple, boring but adequate solution.