Versions prior to 9.3 allow UFS, though jails are only supported on ZFS. I think you can get jails running on UFS prior to the 9.2 series, but I don't recall that clearly.
I'd suggest you install FreeNAS under VirtualBox and see what it has to offer. If it's compelling, save up and build a proper system. There are other NAS systems that can be put together with lower requirements.