In the early 90's, Sainsbury's was doing a lot of deceptive pricing, with 'sale prices' that referred to a totally different "was" price. I was new to the UK, and very conscious of prices, and at that time I could actually remember what I had paid for everything. I wrote to Sainsbury's about it, and got a really nasty reply.
Some weeks later I wrote again (this was pre-internet days) regarding 2 of their own brand products, and how disappointed I was in both. In one case it was laundry detergent. I thought the stuff wasn't doing the job, but said nothing, then DH asked why his work clothes weren't getting clean. Again, Sainsbury's told me "tough $#!t".
The point of all this is, I still pay great attention to prices and quality. Sale prices aren't always a good deal and indeed it is well to make sure the 'sale' is worth the expenditure.