You could, for those customers, give the software away for free but charge for each support request? This cannibalizes the primary value you're creating and yo

You could, for those customers, give the software away for free but charge for each support request? This cannibalizes the primary value you're creating and you're going to get people arguing about every single support request. If a customer thinks they can get professional work done for $2 an hour you say "Interesting. I wish you the best of luck in your endeavors." and write them out of your life.