Are there any cheap remote access programs/services that allow me to access more than one computer?

I "work" for a small company and have sort of become the IT guy. However, I'll be moving away/back home soon and my boss still wants me to be the IT guy. She's hoping that maybe there is some program that will allow me to access the computers remotely from home so I can still fix them if needed. As far as I can tell, all the programs I can find are around $20 a month and only allow access to a few computers. Are there any that are cheaper or allow for me to access around 4-6+ computers?