Seeing as there is already the capability to run a built in ftp server on OS X why bother downloading and potentially paying for one?
Starting the OS X FTP Server
sudo -s launchctl load -w /System/Library/LaunchDaemons/ftp.plist
Stopping the OS X FTP Server
sudo -s launchctl unload -w /System/Library/LaunchDaemons/ftp.plist
You could even easily knock up an Automator app to start and stop this (sod it I might even make one myself).