Time is money. And time is something you never get back.
Someone wise taught me a really good lifehack.
Everytime you look towards shopping something you dont need, break it down into time.
Example, you wanna buy a jacket for 100 bucks, how many hours at your job does that equal to? Let's say its 3hrs.
Now ask yourself, is that jacket worth 3hr of my time?
Let that steer your choice and most probably you will see how much your spending starts decreasing with time :)