For large programs, you have to put down many thousands of euro. But I don't want to design anything other than face buttons for a game controller, and a part a few millimeters high is enough for me to stick on the buttons on the Astro C40 or PS4 or XBox controller. These should enable the buttons to be felt.
I personally use OpenSCAD for 3D files (.stl). It's free but very mathematical.
Alternatively, you can use 3D Builder from Microsoft or modeling software such as Blender for very simple tasks. Both are also free.
There's free software (e.g. Freecad) that can be used under Windows, Linux, Mac. Then there's software that can be used free of charge by private individuals, e.g. Autodesk Fusion 360.
Blender would also work for your buttons.
