Automating patch deployment

We have two networks, one AD and one NT4.0. We can not use AD to deploy MSI patch packages to workstations that are not part of the AD (Active Directory), but are part of the NT domain. Not really interested in purchasing SMS as it seems too costly (why should we?). Considering HFNetChkPro 4 to automate the deployment of patches to our workstations and servers, as doing it manually is far too costly and time consuming for the company. Are there any other utilities or software that anyone (possibly free?) recommends that could be used to simplify patch deployment and management to every workstation and server. We use Windows NT, 2000 and XP workstation products, and NT4.0/2000/2000 Adv server products.

Thank You,

George K. Peek
Network Specialist
Allstate Ticketing