Think about it from an airline's point of view. They have hundreds of CVs from FULLY QUALIFIED applicants, by which I mean fATPL/ME/IR with Class 1 medical, MCC and the right to live and work in the country they are applying to. Why would they bother taking on someone who doesn't have evrything? The only exceptions I can think of are when you have a 'contact' who is swaying things for you or you are filling a course start date at short notice and they have the ability to tag on the MCC qualification.
So unfortunately, if you don't have multicrew experience and you are trying to get a job on a multicrew aircraft you MUST have the MCC (be it bought before you start, or provided by the employer). If you don't have one when you apply you are severely restricting your chances of employment.
PP