Invoice Ninja
Free and Open Source Invoicing, Expenses & Time-Tracking
...It offers a plethora of great features, including custom branded invoice design, recurring invoicing and auto-bill clients, real-time quote creation and custom proposals, expense reporting and so much more! Invoice Ninja is also capable of handling online payments from more than 40 payment gateways, including Stripe, PayPal and WePay. It also accepts payments using credit cards, ACH, Bitcoin and more. Get paid online, organize project workflows with Kanban Boards, and track time online via your Webapp account all with Invoice Ninja.