Microsoft Office price is really reasonable?

I think the most of you have use Microsoft Ofiice(MO), but you don't know it's very expensive software. The price of Microsoft Ofiice Standard 2007 is nearly $400 as a retail product. In economy, if the more number of user bought a product, that price will be getting more reasonable. But MO is not getting more reasonable. The price is against economics. On the other hand, we can use some FREE office suite now; Google Docs & Spreadsheets, IBM Lotus Symphony and OpenOffice.org. Each isn't copy of MO but MO-compatible suite. I think these FREE office suites are good software individually. But people always require high LEGACY-compatiblity. Which is more reasonable price?