Is it permissible to purchase a house in Spain with bank installments that include an increase in price, given the impossibility of renting a home due to racism, and the very high prices of houses?

The fundamental principle is the prohibition of dealing with usurious banks due to the severe warning against usury. Therefore, it is not permissible to borrow from them to purchase a home except in cases of urgent necessity, such as the inability to secure housing through permissible means or the inability to rent. If this becomes impossible, then borrowing from them is permissible, in accordance with the Almighty’s saying: "And He has explained to you in detail what is forbidden to you, except that to which you are compelled."