Hi KT,
Like everyone else I also welcome you to NZ and to pregnancy. I'm originally from the UK and am having baby number 3 over here. We emigrated 11 months ago and I'm 8 months gone now, so clearly NZ's clean living is doing us both some baby-good.
If you're from UK or Oz, then maternity services are free, and if your partner is a kiwi then it's free too. But it is best to check with your LMC. There isn't any need to see your GP who will only give you a Bounty pack and info on LMCs in your area, which you can do by looking in the yellow pages and your LMC will give you the bounty pack at your first appointment anyway. You'll save yourself $40 in GP fees. Most GPs don't have anything to do with maternity services so there's really no need.
This site is also a godsend. So much information here.
I'm pretty sure you've researched what not to eat etc by now, but folic acid 800mcg daily is advisable and not all pregnancy vitamins actually contain this amount so look carefully.
Trade Me is a good website to look for baby stuff, also buy sell and swap, local bulletin boards in villages and local papers that are delivered free. There's also one day sale sites that you can get some pretty cheap stuff on. I use onedaysalefinder.co.nz and log on daily to check out discounts, it's loads of random stuff, but I love it.
On the pregnancy side of things: ultrasounds are not free, I pay $40 a time and if you're in a high risk category then you'll have quite a few. Blood tests are free as are all visits to LMC and related necessary obstetric services.
If you're new to NZ, then check out with the IRD what you're entitled to when it comes to maternity allowances, your baby will be an NZ citizen I think if one parent is also NZ but go into the IRD office and speak to someone directly, if you phone them, they're useless, I've spoken to 4 people and got 4 different opinions or decisions on what I'm entitled to. At least if you do it in person, they make a record of it and you can get a name and know what they look like if you need to speak to someone higher up the chain.
I'm sure that there's loads more, but I've got preggers brain and can't remember, I'm also knackered and bubs is kicking my bladder again so I'm off to my usual spot in the house.
Good luck with it all.