Earlier this month, we reported that Sprint was starting to knock $50 off of its iPhone 4 and 4S models. Then a week later, Apple started matching the discounted prices at its retail stores.

Now it looks like other carriers want in on the action. Over the weekend, discounted AT&T and Verizon iPhones started popping up in Best Buy and Target stores around the country…

PCWorld is reporting that multiple retailers are now offering AT&T and Verizon-branded iPhones at a $50 discount. This means that the iPhone 4 can be purchased for as low as $49.99, and the iPhone 4S as low as $149. We’ve confirmed the pricing with both Best Buy and Target.

The marked-down prices come amidst a flurry of reports that Apple is planning to unveil a new handset next month. Word is, the company will unveil the new smartphone during a media event on September 12, offering same-day pre-orders, with a release scheduled for the following week.

Product sales for Apple do generally indicate a refresh is coming, as not only is it trying to clear space in its warehouses for new models, but it’s trying to keep sales steady. Remember, the company attributed last quarter’s missed iPhone sales projections to rumors of a new handset coming.

That being said, if you’re looking for an Apple smartphone and have no interest in the latest and greatest, it may be worth checking out your local Best Buy or other retailer right now. Keep in mind that these prices come with a two-year carrier contract, and appear to be available in-store only.