DxO Optics 9 is completely free to download until February 28th, 2017. It's a great RAW photo processor that works with your specific camera and lens to correct their common "defects" such as noise reduction, chromatic aberration, and vignetting - but there are some caveats. The list of cameras it supports is dated and higher end cameras are completely excluded. You have to give your email address. But if you're camera IS supported why not give a run? Their version 11 is out so it's safe to say this is truly a free giveaway and there are no complaints I've seen about hassling or haggling for money or upgrades.
CLICK HERE for a list of cameras that are supported.
CLICK HERE for your free copy
I am in no way affiliated with this company or its products so if you have any technical difficulties or questions, you'll have to contact them. I'm just letting you know about the free deal.