When we see that deal or a flashy discount label we naturally get a little excited and suddenly our mind is altered to accepting a product that might not be worth it or a good value for what you need.
What can you do? Have a plan, be prepare for it and be aware that we all do it, catch yourself when you see that discount and ask yourself a question. Do I really need this, is it on my list, am I aware of this strategy? Just being aware alone will make you look at deals in a different way.