Invoice Ninja - Invoice Ninja is a free, open-source solution for invoicing and billing customers.
Hub Planner - Transparent Resource Scheduling, Timesheets, Vacation, Resource Requesting, Project Management & powerful Reports in an agile designed, feasible & intuitive software for simple planning
Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.
teamdeck - Teamdeck is a SaaS resource management tool with resource scheduling, leave management, time tracking and timesheet, and customizable reports features. Selected by Hill-Knowlton, Stormind Games, Wunderman Thompson. $3.60/per member.
GnuCash - A personal and small-business financial-accounting software, licensed under GNU/GPL and available for Linux, Windows, Mac OS X, BSD, and Solaris.
Runn - Runn is a real-time resource management platform with integrated time tracking and forecasting. Intuitively plan projects and schedule resources across the short and long term.