You need to stay disciplined. Do not buy things simply because they are a ‘good deal’ relative to their usual price. You wouldn’t have paid that price anyway, so you aren’t saving money compared to that price if you make a purchase. You know how I know you wouldn’t have paid that price? The very fact that you didn’t buy it already.
There may be things you have in your purchase path already. Those are the things to consider buying on Black Friday.