You can get a free license for Fetch if you meet one of these conditions.
"Use by a student or employee of a public or accredited private school, college, university or academy; use by a student or parent engaged in home-schooling; use by volunteers or employees of a tax-exempt charity, to further the work of that charity. Use by government agencies or government research laboratories does not qualify."
Terry O'Leary - Transmit supports SFTP, and to connect using SFTP you just have to select to connect as SFTP instead of FTP in a drop down menu when entering the info to connect. It's an awesome program.
My favorite free FTP client has to be the one built into OS X, great for transmitting one file and such. (And when your terminal is customized to how you like it, its almost enjoyable.)