Amazon pays the most for your iPhone.

A blog post published in the Wall Street Journal shows an interesting chart that somehow benefits users within the United States when it comes to trading or negotiating for one of Apple's mobile phones, from the iPhone 4 to the 5S.

In recent days, the resale of iPhones has become a way for those who want to wait and upgrade to the new iPhone 6, which could be unveiled and arrive in the United States in less than 15 days, to negotiate a better deal.

To compare resale options across different vendors and carriers, a chart has been released showing the price relationships between various providers . It clearly shows that Amazon, the major online marketplace, offers the best price for those looking to trade in their old iPhone. However, this offer is only available in exchange for a gift card.

AT&T, Verizon, Sprint, and T-Mobile are the selected carriers that sell Apple products and are considered the leading phone companies in the United States. Apple even has a program where you can sell your iPhone, but the price they offer is almost 50% of what you can get on Amazon, considering that you receive an Apple Store gift card as payment.

If you want cash, you also have the option of selling your old iPhone 4 or even the latest iPhone 5S for no more than $350 with Glyde , according to the graph, although on the same website the best valuation to sell it quickly does not exceed $270.

The WSJ also published another comparative chart last week on the trend of users who plan to upgrade or change their current iOS device for the new iPhone 6 that is expected to come with iOS 8, but the results show that no more than 50% might make the " upgrade ".