You can use a simple Excel or Google Sheets template with columns for date, source, gross income, fees, and net income, and then use SUMIFS to auto-calculate totals per quarter. I had set up a similar system for a client running an e-commerce business. You can their site structure as well: Adult Cotton Pajamas | Short & Long Sleeve Bottoms For Comfort – Leveret Clothing . It made quarterly reporting much smoother and audit-friendly.