Other than the free database download of the quarterly NCCI edits (which is definitely NOT an easy to use scrubber), I am not aware of any free tools. Some EHR software has scrubbers built in. You pay for the EHR, but the scrubber portion is free.
I use Codify simply because that's what my employer pays for. I agree with orthocoderpgu that scrubbers are well worth the cost. I know my Codify subscription also includes lots of other helpful tools besides the scrubber (more in depth code descriptions, NCDs easy to find, RVU and wRVU #s, global days, applicable modifiers, some additional CEUs, etc.) When we were in a private practice and watching every penny, I still had on online subscription, it was for SpeedECoder, which at the time I researched (> 10 years ago), was the least expensive option that provided what I wanted.
It's the same way I feel about annual coding books. I figure even 1 surgery claim the entire year getting coded and paid accurately is worth the cost.