Do cash sales count as taxable income?

Yes. Cash sales are income when they are receipts from a business or service activity. The fact that no card processor or payer sends a tax form does not create an exclusion.

Fresh example:

• Lena's Repair Bench receives 14,200 by app payments and 3,600 in cash.
• Only the app payments appear on a third-party statement.
• Lena's Schedule C gross receipts still begin with both payment streams.

The exam habit is to separate gross receipts from deductions. Report the receipts first, then deduct ordinary and necessary business expenses if they are properly substantiated.