Yep, in Manawatu, you only get the 12 and 20 week scans as standard. I had an earlier one for suspected ectopic and then 2 later ones for placenta previa. Scans before 12 weeks are free here (so I had one free at 6 weeks), but they make sure they book you in for your nuchal scan after 12 weeks, so you have to pay for it and all the rest, even if they are medically necessary.
Broadway put their prices up between my 12 and 20 week scans, so its now $50 per scan (although I was told it's $170 without a referral because then you don't get the govt subsidy). All up I paid $190 for scans when I was pregnant. But don't worry, she's worth it
I think its cheaper if you have a community services card though?
Even though I had a scan at 6w 2d that agreed exactly with my dates, the 12 week scan put me back 5 days, and that is the one the MW went with for my EDD. Not that it mattered, mind you, DD ignored all such dates and waited until she was ready 10 days later