FreshBooks - The ideal accounting software for small business owners.
Envoice - Send invoices and get paid on Paypal, Payoneer, Stripe and Square.
ZipBooks - ZipBooks is online accounting software for small businesses. 100% free, forever.
Free Invoice Generator - A free invoice generator for startups
Zoho Books - Smart Accounting for Growing Business
Ramp Receipts - Create a receipts/invoice dashboard for Stripe