A couple million dollars a year [1]. It's always interesting to me how relatively little money it takes to make life objectively worse for everyone else in the country while making a small number of people richer. For the cost of a nice house or a low-budget indie film you can make sure taxes are difficult to file for everyone. Of course there's more to the influence these companies have than the dollar value they spend per year but still, it ain't that much money.

[1] https://www.propublica.org/article/filing-taxes-could-be-fre...

I used to do IT work for a very large (>5000 employee) tax/audit firm. They sent out memos at the time telling associates to encourage Obamacare as much as possible in their communities, and to encourage amendments making it more complex, because then they got to bill $250/hour per person to help companies unravel that complexity... I am very glad I am no longer there.