On today's Give Away Of The Day they are offering Online Armour - which according to many of the comments is a great Firewall, some say better than Comodo.
They are giving away the normal (paid) version, not the free version, which would otherwise cost $39.95.
You simply download the install.exe then go to the manufacturers website and 'purchase' the licence key - using a promo code.
During the install process you will be asked for the key.
There are free updates for one year .... but the program does not expire after that.
I have not installed yet (as I am on my work PC) but will do so when at home .... I had no problems with the 'purchase' of the key, or receiving it via e-mail as some others on the site mentioned.
Seems to be a good offer - many of the people commenting on GAOTD run this in tandem with Avast (which I have seen recommended here in several places).