.tk was worth enough some years as many used it when people were not able to afford for domain names and it is still popular.
Here are the requirements you need to meet in order to register a EDU: http://www.educause.edu/edudomain/show_faq.asp?code=EDUELIGIBILITY
I've published on this topic in the past, and as a refresher, will summarize main regulations below: 1. Current Regulations. Currently, new EDU registrations are reserved only for institutions accredited by agencies on the US Department of Education list, and the so-called EDU management organizations (e.g. University of California Reagents), that oversee multiple universities. Legally there is no geographical restriction for new EDUs, and a number of foreign universities accredited by US accrediting agencies have .EDU (e.g. www.london.edu - London Business School). 2. Grandfathered Clause. Prior to 2001, EDU domains were managed by NetworkSolutions, which had somewhat different rules than the current registrar. As a result, when the US Department of Commerce transferred the administration to Educause, they stipulated a grandfathered clause. The grandfathered clause states that any EDU registered prior to 2001 does not need to meet accreditation requirements and other post-2001 stipulations (such as the 1 name per school restriction). As a result, there are many non-university organizations that own EDU, including high schools, museums, associations, and for-profit corporations (e.g. Montgomery Blair High School - www.mbhs.edu; J. Paul Getty Trust - www.getty.edu; Exploratorium Science Museum - www.exploratorium.edu, just to name a few). 3. How to get .EDU Unless you're an accredited school, you cannot register a new .EDU. Neither can you buy an EDU domain as they cannot be bought or sold directly, only through the transfer of organizational ownership. Thus, an individual can only get an EDU by buying an entire school / organization, which owns a grandfathered .EDU (typically, this will be a small school that closed its doors or never took off the ground because of funding, etc.). Avg. price of these deals ~ $15-20K. PM me if you have more questions.
There are only around 4K .edu left I actually have a couple of grandfather one . If someone is interested in development and as a good record and some great idea and resources in the SEO industry I might be interested in something drop me a PM.