UL,
For a comparative price in the US you could contact Sam at heli.com as they run both FAA and CAA license courses.
Otherwise as far as im aware in the UK contact helicopter services at Wycome for costs as they go all the way thru to IR.
I do agree with the above posts that you can have as many ratings as you like, but without the appropriate experience you may well struggle..... a balance is good.
Good luck
R