I am surprised that I have failed to neglect this topic for such a long time.
Some of the most common business applications in use are in the Microsoft Office suite, notably Word, Excel and PowerPoint. If you’ve ever had to purchase this package at retail prices, you were probably amazed at just how expensive this package is, particularly when you only use a small portion of the functionality that they each provide.
The alternative is to use compatible software; originally this meant that you relied on one of many packages that were available in the free-domain. Sun has it’s StarOffice suite which was later released as OpenOffice which over several releases has become the Gold Standard for office suites. It is available on most platforms and is regularly updated. Many features even outperform the Microsoft offerings, my favorite of which is to save just about any document in PDF format.