Budget Pet Products have their Advantix 9 packs at the price of 6 packs! Delivery was free to Sydney. I.e. Advantix blue (25+ kg) 9 packs is $74.43. The cheapest 6 pack I've seen from other …
The advertisement is a little misleading due to Petbarn's prices for the 6-packs (they can be bought for ~$60-65/pack on eBay), but it's still a saving of ~$20-30 compared to buying two of …