What Should I Consider When Building My Own POS System?

You should seriously consider if you plan to process credit cards with your system. If so, there's a need to comply with PCI security standards. This will lead you to think about aspects like source control and integrating with a payment processor. While Excel might be okay for some data handling, you really need a database to manage transactions and ensure data integrity.

Also, think about the infrastructure. If your traditional setup is just a server running in the corner, that's fine at first, but scaling will require more planning for things like disaster recovery and hardware management. Organizations often switch to using cloud hosting or data centers for this as they grow.

I think you should definitely reconsider trying to take this outside of your vape shop without hiring a developer, especially since you mentioned not having any experience with programming languages. I know it could be a fantastic learning experience for you, and you could build on that knowledge for the future.

As for your concerns, there are just too many crucial features that need to be implemented correctly if you plan to sell it to anyone else. Your prototype could serve as a great stepping stone, but make sure you understand the potential security and financial risks.

If you're familiar with VBA, you might find VB.NET a natural progression. ASP.NET is excellent for what you want, providing a solid foundation for developing your app with many features you might need. You might also want to check out Blazor, which is their newer framework and lets you create web apps easily.

For data storage, you'd likely benefit from using SQLite for a desktop app since it's lightweight, or PostgreSQL for a more robust option. But instead of linking the app directly to your Excel files, consider importing your data into a database—that way, you don't risk losing everything if something happens to your Excel doc!