I got mine from iFixit, after ending up with a counterfeit one from Trade Me. I wouldn't suggest finding the cheapest; go to somewhere reputable.

Is it still possible to get batteries from overseas?

Tried making an order from OWC www.macsales.com a little while ago and it said nup and had a blurb about carrier changes and them no longer shipping batteries so since then I havn't been ordering anything with batteries in... Even replaced the macbook Pro battery through Ubertec for a premium. At least their service was top notch.

I Also recommend iFixit

Buying in NZ will be much, much easier. For an expensive computer I'd personally want to go genuine, unless third party is a good brand with a great track record and is much cheaper - saving at least $100.

supposedly genuine local is $100.

it just sh...s me, 3 $200 power adapters that i have treated like my offspring, all because stupid apple wont replace the material they used in the T join law suit which they lost, it still happens in the L magsafe, it gets brittle and cracks. considering you are already paying $3k for well overpriced hardware and a second rate OS (i only use windows 10 now) things like batteries and power adapters which are their fault for longevity shouldnt cost as much as they do.

im not sure ill replace it or sell it. ill only get $600 for the notebook which has a brand new power cable.

i have zero faith in an apple product. until they start doing r n d on their "great" ideas before implementing them.