Yes, many .tk has been offering free domains for many years now.
Although since you never get legal ownership, and pages feature advertising, i would not waste my time developing one. I mean it's not like domains are that expensive to start with.
Also for anyone thinking of using a .tk, following might be of note..
Can I loose my free Dot TK domain name?
Yes, having a free Dot TK domain name does not give you the legal ownership. Dot TK allows you to use your chosen Dot TK domain name as long as you have 30 visitors or more on your domain name once every 90 days. Activity must include website access to your Dot TK website. If you don't have more than 30 visitors to your website in 90 days, your website is either not up or you did not provide any content. That will result in a cancellation of your registration. Your domain name will then be automatically available for other registrants to register either as a free or as a paid registration.