Apple fans will soon be able to trade in their older iPhone models in exchange for money off the iPhone 5 (or the iPhone 5S or 6 if and when such a product launches), according to Bloomberg and a number of anonymous insider Apple sources.

The trade-in scheme will be run by a mobile firm called Brightstar, which already operates similar programmes for carriers in the US, and is intended to encourage the significant number of upgrade hold-outs still using an iPhone 3GS or 4 to take a step up.

Selling refurbished iPhones in emerging markets

Another side of this, however, is Apple's increasing interest in new markets around the world. We recently reported on Apple's recent success in the Indian market, where its iPhones sales more than quadrupled since the start of the year; but the most popular models there were older and less feature-rich models, brought within reach of the expanding Indian middle class by careful discounting and monthly payment schemes.

Selling three or even four generations of iPhone at the same time makes a lot of sense for Apple, since its target markets around the world (and emergent markets like India will be increasingly important over the next few years) are looking for different things. But actually building those various models at the same time is a logistical burden, slowing its factories and reducing the efficiency of Apple's supply chain.

Far better (and greener) to make use of the existing iPhones no longer wanted by customers in the West, refurbish them and resell them at a discount. Even if Apple's per-unit profit is lower in this scenario, it's able to tempt new smartphone users into the iOS ecosystem, giving it a foothold in these growing tech markets where budget options are always a more tempting option.

Budget iPhone concept illustration

A concept illustration of a budget iPhone, a rumoured project that would allow Apple to target emerging markets more effectively

Budget iPhone

On a related note, unconfirmed rumours suggest that Apple may be considering launching a budget iPhone specifically for markets such as India, Brazil and China. One theory is that an iPhone 6 will launch at the same time as an iPhone 5S, which will be built from cheaper materials and offer fewer features.