Susan Edmunds of RNZ Petrol prices have dropped below $3 a litre in some places, but how long will it last? Gaspy reports that the average price of 91 is now $3.23 a litre, down 4.5 percent over 28 days. But some stations are significantly cheaper. Prices are still well up on before conflict in the Middle East broke out. S Simplicity chief economist Shamubeel Eaqub said the average family would buy 45 litres of petrol a week. That cost a peak of $157 in the week of April 10, which had dropped back to $147 according to Gaspy pricing. But in February, it would have cost them about $114. The cheapest petrol stations for 91 on Thursday were Tasman Epsom, in Auckland, at $2.925. It was closely followed by NPD Wiri, NPD Leamington, NPD Te Rapa and NPD Rangitikei St, all at $2.926. NPD is running a discount day on Thursday, reducing prices by 15c. Oil prices increased overnight on Thursday on reports that the US was preparing for a long blockade in Iran, which suggested that prices might start to rise again.…