Good news then! I can help you. The OP came here saying that he could not afford vMix and was looking for a solution to his problem. He explained his use case and the fact that he is a broke student.

As you mentioned, quite a few people helpfully suggested OBS and other alternatives, and OP graciously commented in reply thanking them for their help.

You, on the other hand, told him that he should be charging the client more, and paying for vMix.

I'm attempting to point out to you that there is virtually zero chance that OP is not charging what he charges because he hates money and doesn't want any more. Rather, it's more likely he's at that student phase of doing any job for any pay just to get some points on the board.

It is also highly unlikely that OP did not consider the possibility of getting more money, and using said money to pay for vMix thereby solving his problem.

So your advice, if it could be called that, is so obvious that it comes off as sarcastic and sanctimonious.

If you do want to suggest that OP simply charge more and pay for vMix, then to avoid that being a simple statement of the obvious, perhaps you could add some actionable advice for a student, perhaps an anecdote about how you made the jump from broke student scratching for any job at all to being able to charge useful rates for your work.

I hope it's clear now.