It's the season of sales. And many of us are going to get stuffed with as much as we can with the "Sale items".
When it comes to buying, I would suggest to keep your "Rationality" alive. For that, know "how the seller thinks?"
Let me help you with that a little, with your seller's psychology. When it comes to a product, the seller will always do anything to sell his/her product by say, attractive slogans, attractive manufacturing, fair pricing and sometimes such offers like 'buy one get one free'. Yeah it sounds attractive enough to buy.
So, they will do anything to market their product well. But again, it's their business and business is a business. You have to work for it, with that business attitude.
Why a Seller goes for a "Sale" is just another strategy to get more customers. But, question is "What do you see in a product before buying it?"