I asked a sholar. You are not allowed to overprice an item that is in need, knowing that you are taking advantage of the situation. Here are a couple references I was given:
'Iddikhar': The storing of essential needs, especially food, by tradesmen, to raise the price when there is a need or panic buying. This action of 'iddikhar' is haram and the one who does it is cursed in the hadith. Do not extort people and raise the prices. Where toilet paper was £5, the shops have raised it to £15! The Asian and Muslim shopkeepers are robbing people, while the corporations like ASDA and Tesco have kept the same prices. Those shops that are raising the prices mustn't talk about 'supporting local community businesses', and people should remember which shops are extorting to boycott them today, as well as tomorrow when the virus disappears (with the will of Allah). As for buying essential needs like flour, to store and feed your family and others, this is permitted on the condition that you take care of the most needy, like the elderly, the orphans, the ill and vulnerable. Stop panic buying as there are people who then cannot get their essential needs.
Summary of an hadith by Umar رضى الله تعالى عنه: A rich man with horses wanted to buy food for his horses. He offered a high price, which the poor couldn't afford. He was told to either buy little food or migrate elsewhere.