Grabing Sale but Price is Still the Same

The absolute discount is exactly the same, but the relative discount is much smaller in the first discount. We prefer to get 50% more of the same product for the same price than save 33% on the price, even though that comes down to exactly the same thing. We like it better when they give us 25% discount on top of a 20% discount, instead of a single 40% discount. And again, it comes down to exact same discount. A ₱500 discount on a ₱5,000 will be regarded as much less than a ₱500 off an ₱1,000 product. 

A wording like "Get ₱ off" will motivate people to buy more even if the other products are not actually on sale. The wording has a lot of impact on how people perceive the discounts. We more likely think if we are to achieve a gain or more likely to avoid a loss? We have this perspective that if we don't buy the product now, at the discounted price, we are likely to miss out on saving some money. There is urgency involved. That anticipation of missing out is exactly why discounts works

Reference:
https://yoast.com/psychology-discounts/