What is the ruling on the Islamic Murabaha offered by banks that deal with usury, where the bank buys what the client wants and then sells it to him in installments?

The basic principle is that a Muslim should deal with Islamic banks. However, if this is difficult and one can only find a usurious bank that conducts some of its transactions according to Sharia principles, such as a murabaha sale with its stipulated conditions, then there is no harm in that. It is permissible to deal with a usurious bank if it offers lower costs for the Sharia-compliant transactions it undertakes.