Envoice - Send invoices and get paid on Paypal, Payoneer, Stripe and Square.
flyceipts - A fresh look at digital receipts & other documents.
Free Invoice Generator - A free invoice generator for startups
QuickReceipts - A mobile app that automatically tracks, organizes, and stores your digital receipts privately on your device.
Invoice.to - A simple & beautiful invoice generator with Stripe & Paypal
Receiptful - Receipts that increase CLTV. Exclusive (early access to PH)