We have a code for 3,000 Nectar points with a £75 online shop with Sainsbos. Never shop with them normally, do Aldi weekly then Tesco/Asda once every 6-8 weeks.
With Xmas coming up (we have 12 people & 4 dogs for lunch!!) we know we will need to a biggish shop at one of the big supermarkets so is this deal worth it when Sainsbos are likely to be more expensive than Asda/Tesco?