Still supply and demand.
Local hardware stores and gas stations raised their prices because more people were shopping at them and they adjusted their price to meet their supply constraints. If nobody shopped, the prices would drop. When items are coming off the shelves faster than they can be replced the prices go up.
Gas stations set their prices to be competitive with other gas stations in the area and to keep their tanks cycling. If you owned a gas station and didn't raise your price to be on par with your competition you would quickly sell out for less profit than your competition. You would not stay in business, as you wouldn't sell more fuel, you would just sell it for less than your competition. If you owned a hardware store and knew that you were going to sell out of merchandise before you could replace it would you keep your prices the same, or raise them to meet the demand? Sorry to say, but people go into business to make a profit. As much profit as possible! This being America, anyone can open their own business and charge whatever they wish.
Do you own a house? If you went to sell your house tomorrow would you sell it for a fair price that made you feel morally right, or would you sell it for what the market could bear? Even if you could make a huge profit? Would you be gouging to make 3-4 times profit in 5 years, as we could selling our house today?
Anything is only worth what a person is willing to pay for it right now. The fuel at the gas station has absolutely no value until someone sticks their credit card in and starts pumping.
Greg