This is not as simple as it sounds. Just yesterday I had a call with the Delft university of technology in Netherland, they want me to add some features on the free version of my FOSS product [1] but they did not want to pay anything. Over the last month, I was in contact with a 800B publicly traded company for a 1.8k per year invoice, once we agreed on the general direction they kept adding expectations, first was to sign tons of paperwork with their security checklist, legal stuff which took a few days but when they start asking for things that would take potentially weeks more, I invite them to do extras on a contracting basis, since them I have never heard back and of course they never paid a dime. I have literally tons of stories like this from governments to F500. In my bubble the paid support plan mostly work with US entities.