For those of you involved with vulnerability assessments or anyone interested in getting your hands on one of the best tools in that area: Tenable recently made available the Nessus Essentials edition that is limiting your scans to 16 hosts at a time, but without any restrictions on its use.
See https://www.tenable.com/press-releases/tenable-launches-nessus-essentials for details, registration and downloads.
Things to note: If you have newer version of WinPCAP or NPCAP drivers installed, you may have to uninstall those and the dependent programs before installing Nessus.
