How to create a buy now pay later app like Tabby

Building an app like Tabby with a mid-level UI and technology can cost between $37,000 and $62,000. But the price of an application with several advanced technologies and a high-end design system might cost around $160,000 or more.
These applications operate in a very simple manner: Go to a retail shop, purchase the item, select the "buy now, pay later" option, and pay a small portion of the total amount due, and the remaining balance can also be paid in installments. The money can be paid directly through a bank account or credit/debit cards.