I'm looking a for a really cheap case, under $160 AUD and fit a Corsair H100i without any modding at all and without Push/Pull set up. Any ideas would be greatly appreciated.
The HAF 912 supports a 240mm rad inside top.* It is about a $60 USD case here in the States. I presume it is within budget in your part of the world. I have one in my sig. below. I wouldn't call it cheap by any means, just not very expensive. But very well made and designed. It also comes in a black interior version if that is your preference. http://us.coolermaster.com/product/Detail/case/case-series/haf-912.html
*My Corsair H60 rad/fan combo is ~47.6 mm deep or thick. I presume the H100i rad/fan assembly is the same thickness since it uses the same fan and rad (except longer). That would bring the fan down to slightly below the top edge of my MB if I had it top mounted. Of course, you'd have to lose the rear exhaust fan.