Generally, mobile banking applications with simple features can be developed at an average cost of $50,000 and a digital banking app with more enterprise-grade and complex banking can cost around $150,000. 

The cost of development also varies on the basis of the company and the geographical location of the developer. Of course, a mobile app development company in the USA, UK, are more expensive than mobile app development companies operating in India

On a wider picture, the process of digital banking app development looks like a lot of work, and also a huge investment of money. If you wish to own an app like raknbank, you should start thinking about different processes that can be automated or about banking products that can be invented to get most of their advantages.