The question I ask myself a lot of times whenever I go to the mall to see sale items is whether they are really on sale or not. I mean, there are stores that only change the prices of their products to make it seem like they are on sale. One time, I saw a badminton racket which was "on sale", but the price was much expensive than the one I saw at the other mall which was not on sale.
I think this is a practice employed by many retailers, both online and offline, so personally what I just use as a standard of measure when deciding about these things is to rely on what I would be willing to pay for for the item regardless of what I would be saving, because after all even if the deal were good, if I wouldn't have money for the rest of the month if I bought that item then it wouldn't be such a practical purchase regardless. I think in general it's best to do research before buying the item especially I since we can do that now on our phones but if myself don't always feel up to doing it before each purchase so I just rely on gut feeling instead.
Really some stores do that sort of practice that you saw of the badminton! I shop at CVS and other retailers in Hawaii and their sales are always legit. You can get a 2.49 11 oz. potato chip for 2.00 on sale for example. I just bought a chuck roast Angus bone out for 3.49 a pound at Times Supermarket which usually goes for 4.49 or 5.49 anywhere else on island of Oahu at the moment. So the sales are legit. Maybe the store has a bigger markup than the other store or rent is higher so they charge more. I go to 3 different Walgreens store for cigarettes and they all charge differently for 2 packs of Pall Mall (I know I should quit and on my way to quit too). The different charges are 12.76, 13.10 and 14.10.
In the last 10 years or so, there are stores that put on sale real sale items, i.e. products that are good but with a good discount. When I was younger, I used to see the word sale on some items but I do not mind it simply because the sale is fake - the items may be defective or too old, clothing materials have torn parts or soiled or stained. Until now, there are stores that put on sale such items. You just have to be discerning.
Some items are not really on sale, but discounted compared to the RRP (recommended retail price), however, often that price is never charged. By law in the UK there must a declaration if an item has been advertised cheaper, the price and when. It's usually tiny print at the bottom or indicated with an asterisk. It also depends on the shop and whether they offer genuine discounts or not. Most stores will have a special offer, but that doesn't mean it's always discounted, but maybe a special buy.
When retailers want get rid of some items for any reason whatsoever the prices will be marked down. It could be because they don't expect those items to be sold for a really long time for example. However most of the other items aren't really on sale. Since the retailers will be making a profit anyway, I'd say they sell those items closer to what they are supposed to be sold at.
That is one marketing trick of some companies, they just place the sign "sale" onto their items but in reality the price wasn't slashed down at all. I did read a blog narrating that exact same strategy in The Body Shop where the price of item was the same before and after they marked it "on sale", so it really pays to take note of the prices to be sure.