QuickReceipts - A mobile app that automatically tracks, organizes, and stores your digital receipts privately on your device.
Invoice Ninja - Invoice Ninja is a free, open-source solution for invoicing and billing customers.
Receiptful - Receipts that increase CLTV. Exclusive (early access to PH)
Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.
Keep Your Friends Close - A free e-book about maximizing Customer Lifetime Value
FreshBooks - The ideal accounting software for small business owners.