5W-30 Long Life $31.95: https://www.ebay.com.au/itm/142394637624
Specs: https://www.nulon.com.au/products/full-synthetic-engine-oils…
5W-40 Long Life $31.95: https://www.ebay.com.au/itm/142394637774
Specs: https://www.nulon.com.au/products/full-synthetic-engine-oils…
5W-20 Fuel Conserving $33.95: https://www.ebay.com.au/itm/132205070139
Specs: https://www.nulon.com.au/products/full-synthetic-engine-oils…
0W-20 Fuel Saving $34.99: https://www.ebay.com.au/itm/203052652577
Specs: https://www.nulon.com.au/products/full-synthetic-engine-oils…
10W-40 Hi-Tech Fast Flowing $31.95: https://www.ebay.com.au/itm/132205071085
Specs: https://www.nulon.com.au/products/full-synthetic-engine-oils…
5W-30 Low Emission Diesel $32.99: https://www.ebay.com.au/itm/142394650586
Specs: https://www.nulon.com.au/products/diesel-engine-oils/full-sy…
5W-30 NEXT $25.99: https://www.ebay.com.au/itm/234091325195
Specs: https://www.nulon.com.au/products/full-synthetic-engine-oils…
10W-40 NEXT $26.99: https://www.ebay.com.au/itm/194242134190
Specs: https://www.nulon.com.au/products/full-synthetic-engine-oils…
Full range from various sellers: https://www.ebay.com.au/e/coupon-offers/march-plus-deals-mar…
EDIT: Updated prices and links due to price jacking.
How does it compare to the Castro synthetic oil?