They charge fees from the interns (most of the time) for project saying that they would teach the particular technology first and then they would help in the project. That ways, the project becomes free but the it becomes compulsory to learn the technology by them. But the trick is, they don't teach anything. The developers are only the faculties to teach and the students are their secondary priority. It is a sheer waste of time and money interning with them. They hardly teach 2 hours in 6 months.
Students who are smart, build the project by themselves on finding no help. But those who are average students or dumb students, can never finish project under them. During submission, the company builds a prototype or gives an already build project to such students.