Couple of suggestions
A. Have really rich parents who will pay for those hours.
B. Be really rich all by your self (which means you do stuff other than fly), then you can pay for 300 hrs multi yourself.
C. Speak to some operators like Sharp Aviation or King Island airlines who have been known to do ICUS deals (still going to cost you!). Listen to what these types say, learn how to operate these aircraft really well. Then do what it takes to build experience. Then in a few years you will have more than 300hrs Multi and you will know how to fly, be employable and live happily ever after.
A and B are much easier.