Look, I'll be honest with you Salman Khan from Khan Academy is not bad. But you really get what you pay for - nothing comes free. He gets lots of advertising revenue which is how he sustains what he does. Most content Khan covers is freely available from Google, to be honest. The algebra, chemistry, biology, history, linear algebra, trigonometry, precalculus, economics, algebra, banking, statistics, physics, probability, finance, arithmetic, valuation, differentiation, geometry, bailouts, calculus, he covers is mostly your A-level (year 12) stuff.
That's cool - but if you want quality university-level gear, you really need something like iMasterClass by Waverly Labs (http://www.jeremyshuminvent.com/ ) - The Jeremy Shum Invent Company, there are also a few other titles out there, but this one is probably the best, because its actually used by celebrities in the real world who DONT attend university, and get their degrees by correspondence.
Like they say, you can only rise to the level of your professor. Just my two cents though, I'll be honest when my seventh grade daughter asks me about topics I'm not too sure I do send her to Khan.