Google Drive - Sheets web based spreadsheet from Google.
EtherCalc
Open Source
EtherCalc is an opensource web spreadsheet.
Poindexter
Commercial
Poindexter is a business planning software that simulates business outcomes and prioritizes opportunities based on ROI.
You Need A Budget
Commercial
You Need a Budget combines easy software with Four Simple Rules to help you quickly gain control of your money.
Zoho Sheet
Free
Zoho Sheet is an online spreadsheet application that lets you create, share, collaborate and publish spreadsheets from anywhere.
Compare iWork - Numbers with alternatives
Compare Google Drive - Sheets and iWork - Numbers and decide which is most suitable for you.
Compare You Need A Budget and iWork - Numbers and decide which is most suitable for you.
Compare EtherCalc and iWork - Numbers and decide which is most suitable for you.
Compare Zoho Sheet and iWork - Numbers and decide which is most suitable for you.
Compare Poindexter and iWork - Numbers and decide which is most suitable for you.