How long is a piece of string?
The Robinson Factory have I believe nearly spot on prices for the LifeEx rebuild, but it really will depend on many things, firstly what do you want in the rebuild, and is the A/F good enough.
The value of something that is LifeEx is controlled by the willingness of the person who wishes or wants to buy such a crate, from memory you can find R22's with plenty o life in them from about £40K. you need to look around !
Regards
PeterB
Vfr