Dropbox provides LAN Sync for PCs to save time & money. Is there any way to enable it for Android devices? All Dropbox sync apps use only internet for syncing.
What you can do is use both Dropbox and a LAN syncing tool like Unison. I couldn't find any LAN syncing tool for Android but if you mount your device in Mass Storage Mode, running Unison purely on your PC should yield acceptable performance. It may also be possible to compile Unison on Android (it works on GNU/Linux), but that would be fairly difficult.