Anyone have suggestions for small business CRM software?

I'm trying to find a basic CRM software for my Dad's business but there's always one feature missing or its out of price range.

He's basically just looking for somewhere to store client files (PDFs and spreadsheets) that they can access. But the key is that they are automatically notified when files get uploaded/ updated.

Budget is about $500 USD per year (which is $800 AUD).

I've tried SuiteDash, Plutio, Copilot, Agiled, and more, but I know I've probably missed heaps. Any suggestions would be greatly appreciated, I feel like I'm going around in circles!