SUSE has been a Linux distributor since 1992 and was acquired by Novell in early 2004. Originally, SUSE provided a free downloadable distribution, for which support contracts could be purchased as required.
Eventually, the SUSE product line was split. Novell now markets SUSE Linux Desktop, as well as SUSE Linux Enterprise Server (SLES).
SUSE Linux Desktop is free to download, but SLES is available only with the purchase of a maintenance contract.