My best would have been the EK MEL-AKL, AUD$99 each way.
Got the email offering J upgrade for AUD$130 to AKL, and then upgraded to F for free, so AUD$229 for F from MEL to AKL.
On the way back, got the same offer for NZD$130 and upgraded to J.
Got the email offering J upgrade for AUD$130 to AKL, and then upgraded to F for free, so AUD$229 for F from MEL to AKL.
On the way back, got the same offer for NZD$130 and upgraded to J.