Can I write off the cost of turbo tax fed and state tax along with the audit protection in my 2017 Business return?

Yes, you may write off the cost of your tax products as an expense in the year you purchased them.

For instance, if you are speaking of the 2017 products, you may write those off in 2018, as this is when you are purchasing them.  The products for 2016, which were paid for in 2017, may be taken as an expense in 2017, and so on.

Thanks, just to be clear, If I purchased TT products in 2018 for my 2017 filing, I write them off on the 2018 return, not the 2017 return?

Correct.

Thanks!