Sorry - can't help with the costs...suggest a look at the Flight Safety website.
The FAA (and I think the JAA) group the 500/550/560 as one type rating...although you might (?) also have to do an EFIS course if you were to fly a 550 Bravo or one of the other glass cockpit variants.
The 525 is a separate type - don't know if the CJ2 will be the same type rating as the CJ1.
The Excel is also a separate type rating.
Good luck - I'd suggest picking the type that you're likely to get to fly...it could be a long and expensive process otherwise!