The cheapest petrol in Sydney according to the Fuelcheck & Petrolspy @ BP Clovelly. Only U91 & 98 though
BP Address: 33-37 Carrington Rd Clovelly, NSW 2031
If you don't want to wait in line, Sparkles Petroleum down the road also has 95, is also fairly cheap + BP Randwick also
Not 7-11, hence sorry no choppers but if you're a stickler for branded fuel then bring your jerry cans
Edit 6/8 8am Further Drop: [NSW] E10 @ 115.9 / U91 @ 117.9 / U98 @ 135.9 - BP Randwick/ BP Clovelly
You can also check this thread: [NSW/ACT/QLD] Fuel Watch if you want to see other location/pricing/comments.