Multi PC NAS Backup

[kerncraftergold]

Hey all,

I've recently gained a thin-and-light for school.  As school is mostly online/computer based, I have ran into an issue.  In actual class I use my laptop, however, after class (doing my homework or whatever), I prefer to use my gaming rig.  

I have a WD 2TB NAS, and was wondering if there was a way to backup a folder to the NAS from both PCs (when connected to that network) but also download the latest version on both PCs--effectively having the same folder/files on two devices at once (with a backup on the NAS)

In a way, I'm looking for something of how Apple's photos app works (from iPhone to iPad), but for a folder with various filetypes on Windows.

I would prefer a free or one-time low cost software to do this.  

TO BE CLEAR: I DO NOT want a cloud based service.  If I don't have internet access, I STILL need to be able to do my work.

[Sjaakie]

Look into Syncthing!