I think that "cheap K fares" is an oxymoron..the whole idea of these fares is that they are only slightly discounted from full economy.
It used to be (and I think still is?) possible to get effectively 'free' domestic K fares by booking an international flight in K with domestic connecting flights. However, that defeats the purpose somewhat!
[This message has been edited by whughes3 (edited Jan 06, 2004).]