SlickPie Alternatives

GnuCash is personal and small-business financial-accounting software, freely licensed under the GNU GPL and available for GNU/Linux, BSD, Solaris, Mac OS X and Microsoft Windows.

Odoo (formerly OpenERP) is a suite of open-source business apps written in Python and distributed under the AGPL license, under the Open Core software business model. It is used by 2 million users worldwide to manage companies of all size.

Full-featured work and project management solution dedicated to project-based small businesses and teams who want to manage projects from start to finish.

InvoicePlane is a self-hosted open source application for managing your quotes, invoices, clients and payments. The application comes with various options, templates and settings to customize your invoicing experience.

Wave makes it easy to be your own boss. Just do what you're good at, and lean on Wave's smart online software for help with invoicing, accounting and payroll.

From invoicing to expense tracking to accounting, Akaunting has all the tools you need to manage your money online, for free.

Painless invoicing with stunning customizable templates.

Crater is an open-source app made in Laravel, VueJS & React Native that helps you track expenses, payments & create professional invoices & estimates.

Insightly is a web-based project and Customer Relationship Management (CRM) application that integrates with Google Apps via a Gmail contextual gadget and Google Docs support.

BILLmanager is a highly customizable billing software for hosting and IaaS business with the full scope of functionality for billing, service provisioning, client management & support.