The seasonal variation in prices in NZ is much more than in the UK. Having said that, we pay 50c/ capsicum when they are available from the small market garden at the western (Mapua) end of lower Queen Street in Richmond. Probably not worth driving from Mapua for unless you are headed that way anyway. In season, we buy tomatoes from the same place for $5 for 5kg for "cooking tomatoes" (funny shapes but nice and ripe) and only slightly more for first quality. There are also a some market gardens around Motueka that are not expensive although I don't know exactly where they are - my parents keep turning up with large bags of produce though - you may need to ask some of the locals.
I feel that we pay significantly less for produce than in the UK, but we eat seasonally.