T-Mobile has phones as cheap as $150 (admittedly probably not great but still work), and quality phones as low as $400 or $500 for lower end or older iPhone/Pixel models. If you don't know if you can spend $150-$500 for a minor emergency, then you don't have an emergency fund which is easily the #1 priority for personal finances. Same for the Aeron - if you don't know if you can afford a $150 chair, you shouldn't buy it. The amount of the sale is irrelevant by the way - buying something you don't need that is 90% off is still a waste of money.