Hi
MBAaustralia, this is a great question to be asking. You'll probably get some differing opinions, but I would allocate your budget towards the following:
1) Help with defining your application 'thesis statement' or 'personal brand' (i.e. what you will contribute to the MBA class, what your future goals are, and why an MBA (specifically on a deferred basis) makes sense. This can be leveraged across all of your applications and feeds multiple other components of the application so it is a good bang for your buck (resume, interview answers, essays).
2) Help with your resume - similar to above, this can be used for multiple schools and a consultant can help you effectively highlight the qualities the adcom seeks in deferred admits.
3) Essays for your top school or two, given their importance to the overall package (particularly for a deferred applicant without formal work experience)
Hope that's helpful. If you'd like to chat more, we offer free 30-minute consults:
https://vantagepointmba.com/free-consultation/. Best of luck!