Some of the transfer fees are stupid, I swear they're still calculated in Yen, and not £/€/etc. I moved to Milan from FC Twente when I was a 20 year old, and my fee was around £25,000,000, despite my OVR only being about 71-72, and not really being a particularly stand-out player.
I've also seen people earning £43,000,000 or more a year in wages, which is like £800,000 a week...even Eto'o doesn't earn that much! it's so unrealistic (especially when you can't spend the money on anything other than a new agent anyway, so what's the point of earning that much?)
As for getting a move to a big club, I think you just have to persist with it for a few seasons...unless you're terrible and are getting 5.0-5.5 ratings every game, you'll usually get an offer from a decent team within a few years, rightly or wrongly. I moved to Milan in my 4th season after playing for Heracles, Bordeaux and FC Twente before that