Best Buy is slashing the on-contract price of Apple's flagship iPhone 5S by $75 this weekend. That brings the 16GB model down to $124.99, one of the lowest prices we've seen for the 64-bit smartphone. The savings also apply to models with more flash storage; the 32GB iPhone 55S is $224.99, and the 64GB is $324.99 with the discount applied. Best Buy's deal is good for any iPhone 5S on Verizon Wireless, AT&T, or Sprint and runs through January 4th. Of course, a two-year contract is required to take advantage, but assuming you're happy with your current carrier, it may not be the worst option. Best Buy is also selling the iPhone 5C for free on-contract through the 4th, so that may be worth looking at if you don't need Apple's latest and greatest.