Any Recommendations for a CRM with Payment Processing and Expense Tracking?

Hello all! I’m looking for a basic free CRM that includes payment processing and expense tracking. I’ve come across Odoo, but are there any others? I’m looking for free for basic features because right now it’s for managing only 14 clients. I would like to automate invoices and payment reminders. Of course it’s fine if there’s cost associated with more features, users, etc. Please let me know of any suggestions. Thank you!