Giant retailer Walmat put the previous generations of iPhone on sale in lieu of the imminent release of the next iPhones.

Walmart now offers iPhone 5 and iPhone 4S for $129 and $39, respectively. It seemed that the retailer is trying to exhaust all of its current stocks.

This move from Walmart is quite shocking since Apple tightly controls how resellers price its products. Thus, we can assume that Apple allowed this pricing strategy.

Moreover, while the California-based company keeps on telling customers that iOS 7 will arrive in the "fall" and tacitly implying that the iPhone 6 will arrive along with it, this very attractive deal from Walmart says that iPhone 6 may be released sometime next month.

Soon, it is expected that the prices of the iPhones will follow previous Apple pricing strategy. When iPhone 6 will arrive, it will be priced at $199 while the iPhone 5 will slide to $99 and the iPhone 4S to free with contract status.

Thus, the current sale could be an attempt by Walmart to get $30 to $40 dollars more for the 5 and 4S now before the iPhone 6 debuts. Also, it could mean that Walmart is planning to receive iPhone 6 inventory shipments soon.

Another evidence that the next generation of Apple's iPhone will arrive soon is that T-Mobile offers discount on the current iPhone 5. The iPhone 5's price has been slashed to just $145.99 upfront on a two-year T-Mobile contract.

The iPhone 5 was available for $99 when it first launched in April, but this was raised to $149.99 in May, after the promotional period.

T-Mobile then increased the iPhone 5 price by $50. Now, T-Mobile has dropped the upfront payment again to $145.99 suggesting a new iPhone may be on its way. However, there is a catch to this as the carrier has also increased the monthly payment, by $1 a month.

Carriers have a habit of dropping the prices of its devices when a new update is announced, usually, to get rid of stock and clear space for the new device. T-Mobile's reduction may be more expensive in the long run, but customers are more tempted to buy if the upfront cost is lowered.

The change in pricing means the device will cost you as much over a 24-month contract as it would if you bought the device unsubsidized from Apple. The 32GB iPhone 5 will cost $245.99 and the 64GB $345.99.

The next iPhone is rumoured to feature Retina or IGZO screen display, A7 quad core chip processor, iOS 7, 128GB internal storage, 13 mega-pixel camera, and longer battery life. The lack of NFC support on the iPhone 5 was one of the biggest criticisms aimed at Apple's smartphone.

Meanwhile, the cheaper iPhone 5S is rumoured to sport a plastic casing, 4-inch screen display, dual core processor and 8-megapixel camera. The smartphone is speculated to be available in five to six different colors.

Both Apple smartphones are rumoured to include a fingerprint sensor technology for added security. The rumour is strengthened by the report that Apple bought a fingerprint technology firm Authentec last year.

However, the Cupertino-based tech company did not give an official statement on the rumours surrounding iPhone 6 and iPhone 5S.