Amazon has introduced Amazon Cash, a way of paying for items on its online store without requiring a debit or credit card.

The service works by sending a barcode, either via SMS – in which case it can be added to the Apple Pay wallet or as a shortcut on the Android home screen – or to be printed off. When a customer takes the barcode into a participating brick-and-mortar store, they can add $15-500 of Amazon credit to their account in exchange for cash.

The service is initially available in the US, with a number of participating retailers including CVS Pharmacy, Kum & Go and Speedway, with more promised in future – but its not hard to imagine Amazon rolling this out to other countries if it proves successful.

The US has a substantial population without bank cards – there are 10m unbanked or underbanked American households, according to the Federal Deposit Insurance Corporation, with the proportion much higher in states like Mississippi, where 16.4 per cent of the population are totally unbanked.

However, those numbers are much higher in other parts of the world – globally, 2bn adults are unbanked, according to World Bank. Most of the unbanked population is concentrated in countries where Amazon doesnt currently operate, though the eCommerce giant has certainly shown interest in expanding globally, with the recent acquisition of Souq representing its first step into the Middle East.