Office 2010 went on sale to consumers and small businesses Tuesday and Microsoft’s free lightweight Office Web Apps version of Word, Excel, OneNote and PowerPoint, its answer to the three-year-old Google Apps, was made generally available. The webby stuff is good on Macs and phones as well as PCs and users with a Hotmail account can make use of SkyDrive, the 25GB of free storage Microsoft offers. To recap, the Home and Student version cost $150 ($120 downloaded); the Home and Business edition, which adds Outlook, is $280 ($200 downloaded); Office Professional, which includes Publisher and Access, lists for $500 ($350 downloaded). Office has traditional accounted for half of Microsoft’s earnings and a third of its revenue, which may explain why it’s spending a reported $80 million to advertise the new stuff.