You really needed to get in earlier for cheaper season's passes -- most of those sales ended at least a couple of months ago. For example, a pass that includes both Coronet Peak and Remarkables (both Queenstown) was $889, and it might have been around another $100 to add Mt Hutt to that list, if you didn't mind moving around the South Island (it's closer to Christchurch).
Another option would be to join a ski club and get discounted passes, plus around 20% off at other club areas for being an affiliated club member. That might, of course, be tricky when you don't live here and can't do work parties to earn your cheap passes, although some clubs do allow you to pay your way out of work parties.
However another option does exist for cheaper skiing, but it depends on bringing someone else and being prepared to travel. We use it from time to time since it's an excellent fundraiser for a worthy cause: the Disabled Snowsports Canterbury voucher booklet. For $110 (and $90 for every subsequent booklet you buy), it offers one 2-for-1 voucher at each of 15 ski areas in the South Island, although not, notably, at any of the nzski.com fields (CP, Remarks and Mt Hutt). The Treble Cone voucher gives you a 3-day pass for the price of a 2-day, and Cardrona 2 passes for 1.5. Many can't be used at the weekends, and there may be other restrictions such as school holidays, but if you do your homework (and bring a buddy), it can offer some savings, and get you sampling a lot of off-the-beaten-path ski fields, from club fields, to smaller commercial operations, to the bigger ones like TC and Cardrona, all the while helping adaptive skiers get out on the snow.