Is it permissible to purchase products offered at very low prices (such as 1 Rupee instead of 10 Rupees) on e-commerce websites, which might be due to viruses on the sites, even if it were possible to inform the sites about these viruses?

If the buyer predominantly believes that the displayed price is an error due to viruses, it is not permissible for him to purchase until he clarifies it to the seller; because the seller would not be pleased with that price at that time, and because some scholars have prohibited exploiting the ignorant regarding prices. If the sale is concluded and the seller claims an error in the price, and the buyer believes him, the buyer is obligated to pay the difference. Moreover, among the ethics of a believer are offering advice and loving good for others. Therefore, he must alert the seller and not deem his money lawful while knowing of the error.