The ruling on selling electrical appliances on installment with an increase in the price

Question:
May Allah reward you. This questioner says: What is the ruling on selling electrical appliances on installment, with a profit of seventy percent?

Answer:
It is permissible to sell appliances, sell machines, and sell what Allah has made lawful to sell, except for forbidden things, which are not permissible to sell. If Allah forbids something, He forbids its price; it is not permissible to sell forbidden things. As for permissible things, it is permissible to sell them, such as electrical appliances and others. It is permissible to make a profit on them, but one should not exaggerate in the profit or go beyond the norm. One should take the customary price that has become established in the market; this is justice. Do not wrong others, do not wrong others, [selling at] what it is worth in the market.