Its not exactly as you state with the licenses. Most (perhaps _all_) organizations/corporates use Microsoft products and have existing licenses. Acquiring more would not be issue in these environemnts.
If you are a start-up, the right way to do it would by joining the BizSpark [1] program. .Net does provide an excellent development and scaleable environment. This program grants you access to all of its products, including Office, SQL server, Visual Studio and a multitude of other applications/tools. There was a recent post on HN [2] that spoke more to this.