If you have a networked multifunction printer/fax/etc., read the manual. Odds are pretty good that even a low-end one supports scanning to FTP, SMB, and email. It's worth checking first (some manufacturers require software on a PC instead of having the capability in the device), but you can get something that'll do this for less than $100 (Brother MFC-J430w supports scan to FTP, as do most Brother devices).