HTC has already gone the trade-in route to offer folks a discount on its new One smartphone, but it's now giving it another go this weekend with an expanded promo in the US and Canada. This new one is open to anyone that buys an HTC One between today and Sunday, May 5th (the previous promotion required folks to pre-register), and it now offers up to $375 for smartphones that you trade-in. Unless you're looking to unload your brand new smartphone in a hurry, though, you may want to check around for the going rates first. The slightly better option is for