It has been just a few days since Apple announced the iPhone 5C, the device is not available for sale yet - and it\u2019s already been discounted by one retailer. Wal-Mart knocked $20 off Apple's price of the phone, bringing it down to $79 if you sign a new two-year contract with your wireless carrier.\n\tThe big-box retailer will also discount the high-end iPhone 5S, and the 16GB device will sell for $189, or $10 off list price.\n\tThe two new iPhones were announced on Tuesday. (Here\u2019s a hands-on look at both.) Apple started taking pre-orders for the iPhone 5C on Sept. 15, but not for the iPhone 5S. Both are expected to be available on Sept. 20.\n\tWal-Mart said buyers can stop by their local store's customer service desk Friday to preorder the iPhone 5C and then come back on Sept. 20 to pick up their devices. Preorders will be filled on a first-come, first-served basis, according to Wal-Mart.\n\tWal-Mart also\u00a0announced Tueday that it will enter the smartphone buyback market and accept trade-ins of older handsets. It said it would offer a $300 credit toward a new phone for a working-condition iPhone 5. Wal-Mart will also accept other smartphones for trade-in; a Galaxy S3 in good condition, for example, will net you $175. (Oddly enough, the trade-ins don't start until Sept. 21, a day after iPhone 5S\/5C sales begin.)\n\tIf you\u2019d rather have cash, checkout Nextworth and Gazelle, both of which will give you a decent price.\n\tDevices you buy from Walmart (and other retailers) are covered by Apple\u2019s standard one-year, limited warranty, but if you\u2019re interested in AppleCare (an extended warranty that covers software as well as hardware and includes phone support) you\u2019ve got to buy from Apple.\n\tAppleCare is a good deal, I think, for more expensive products, like a MacBook or iPad, but at $99 is a rather pricey add-on for a smartphone.