You can buy Office 2013 but the Professional version can be expensive. The down side is that you don’t get a permanent license. You also get free upgrades and best of all you can use the software on 5 PCs or Macs. You get access to the Professional Suite plus 20G OneDrive and 60 minutes of free Skype phone calls/month. You can get started with a trial subscription. Upgrading to Office 2013 365 is very simple.
Note that Windows Vista users, will have to opt for Office 2010. If you need the Professional version on multiple PCs then a subscription is a no-brainer. If you need Office 2013 on multiple PCs then it’s cheaper to get a subscription. The Office 365 Business costs more but it includes a SharePoint website. The cheapest option is to rent Office 365 Home Premium. There are several options for upgrading from Office 2003. Office 2003 updates expire in April 2014 which will leave it vulnerable to attacks.