Re: simple file server for a small office
If you want in house solution & as you said the company cannot spend much .. then here is the solution.
Get a P2/P3 machine with 128MB RAM & large sized HDD(s) (I dont know how much storage do you have & how big backup do u require?)... Install BSD/Linux, install samba over it & mirror it with your actual file server.
BSD/Linux comes with FTP server (proftpd), configure accounts for each user. You can disable SSH access & enable SCP for Secure filecopy for each user too, if u are security paranoid guy. SCP has its own drawbacks though e.g. not very good unless u know exact filenames & their location in ur home directory.