Apple’s iPhone 4S pre-order sales success isn’t the only reason the company’s cash registers are ringing. Price cuts of the existing iPhone 4 and iPhone 3GS have apparently reignited demand for the older handsets, AppleInsider reports, with Canaccord Genuity analyst T. Michael Walkley claiming his checks across US carriers showed buoyant sales of the legacy devices.

That’s even with the promise of the iPhone 4S to tempt them away to the higher-priced model. As well as the new, dual-core phone, Apple announced that the iPhone 4 would be sold at $99 – with a new agreement – for an 8GB version, while an 8GB iPhone 3GS would be offered free.

Walkley didn’t go so far as to share hard figures, so it’s difficult to know exactly how much of a difference the price cut will have made. However, with the promise of iOS 5 later this week for those with the existing devices, it’s entirely possible shoppers on a budget may have decided the updated software and last year’s hardware (or the year before that) was good enough for them.