Cricket Wireless turned a few heads when it announced that it will be the first prepaid carrier in the U.S. to offer the iPhone. However, America’s seventh largest wireless carrier will soon be joined by Boost Mobile, as a trusted source has advised that the prepaid carrier will introduce both the iPhone 4 and 4S in early September. It remains uncertain if the Sprint-powered MVNO will offer its popular $50 Month Unlimited plan with Shrinkage, which includes unlimited talk, text and web, which also rewards customers who pay their bill on time by reducing their monthly bill by $5 down to as low as $35 per month. This is definitely a new era for prepaid as the introduction of the iPhone will likely result in more high-end Android devices being available off-contract. It looks like the postpaid market may have some competition.