This type of discussion most usually ends up with people upset at each other. We unwittingly either get into defensive or sympathy mode. Let's sew something or organize patterns instead! What is reasonable for me depends on many factors. And if the price is somewhat high for one extra-special, hard to find fabric, that I have been seeking for many months, I will buy it, and it doesn't mean that I purchase other fabrics at that price.
I have also been known to buy way more fabric than I needed at rock bottom prices. If the fabric is piled high to the ceiling in my sewing room because of clearance prices, and the house floods or catches fire, or I get gravely ill, I won't feel the least bit happy about how much money I "saved" on that fabric.