Microsoft Office Excel - Microsoft Office Excel is a commercial spreadsheet application.
BillGrid.com - BillGrid is an easy to use online invoicing, billing and expense management system that will save you time with tracking clients projects, expenses, invoices and payments.
Google Sheets - Synchronizing, online-based word processor, part of Google Drive.
ChargeOver - ChargeOver automates recurring billing, subscription billing, & payment acceptance. A SaaS that integrates with Xero, Quickbooks, & has an API. Free trial.
LibreOffice - Calc - LibreOffice Calc is the spreadsheet program you've always needed. A fork of OpenOffice.
Elorus - A super-easy online invoicing & time tracking software