"For today only, this product is 60% off". I've witnessed this one myself - "if you want to sign up for this programme, you have exactly 7 minutes from now. Do it at the back of the hall". A giant countdown timer starts on the screen like a ticking bomb.
Such a technique gives potential buyers little time to think, and plays on their fear of missing out (FOMO).
What to do with this information:
When you are a buyer, recognise these tricks and don't let them affect you making the right decision. Don't hate marketers. It is their job to help sellers connect to their target audience. As a buyer it is your responsibility to understand the product and whether it fits you.
When you are a seller, this is a trick you can use. No matter how well you market, you must still have a good product if you want to stay in business. Do right by your customers.