Pipergirl, I don't really see how doing your ME rating in advance of your CPL is going to save you much money. If you do them separately, then its a 6 hour ME course and test, followed by a 25 hour CPL course, 5 hours of which (+ the test) needs to be in a complex aircraft. By combining the two courses, its just a 28 hour course and one test, 8 hours of which are on a ME aircraft. Plus you don't have to do PFL's on the test if done in a ME aircraft
On the other hand, if you're already close to the 100 hours P1 you need for CPL issue, but still have some way to go to the 200 hours TT time you need, then maybe something like a ME rating would be a good idea, purely because its exposing you a little earlier to complex and multi engine flying.
Hope this helps
PW