for some value of cost-effective. your analysis doesn't jibe with many others. what you can learn at low cost things is not what you can learn from intense classes. and note that damian also teaches at yapc and still offers these classes. they are not the same material nor the same depth. having seen him teach and lecture many times, i would say you get your money's worth from his classes. but then i am biased as i like damian. :-)
as for other people who teach, none that i know of teach for free all the time as they would soon be living on the street. some will offer a class in their home city to the local perl mongers at no or little cost. or they may give a lecture at yapc that covers some of their educational material. they don't teach full time at low rates. the rest of the time they try to earn a living teaching and they charge what the market will bear for their services. the fees for damian's classes have not changed in over 2 years and the market for them is stable.
and while i understand anonymous posting, i don't find it to be helpful to your argument. what have you taught? what classes have you produced? what fiscal/training analysis skills do you have? you could claim anything while behind a mask and not back any of it up.