Is it possible that Trump wants to get richer off his presidency? Is that a bad thing? Should anybody STOP him? CAN anybody stop him?

Of course it is possible, probable and likely. 

Richer is not a concern.  It is how he does it that is.  It is how powerful he becomes not how much he manages to sock away.

The psychological research suggests if Trump IS trying to get richer off of his being elected President, it has much more to do with ego than money.

For example, I once saw an interview with Trump wherein he described meeting with Sidney Frank (the founder of Grey Goose Vodka) and deciding to start Trump Vodka. Not because Trump had any particular expertise in making vodka. Not because Trump was creating a new segment in the vodka market. No, it was simply Trump was hoping his brand name would make Trump Vodka bigger than Grey Goose, so he could win that particular penis-size contest with Sidney Frank.

As for whether Trump should be allowed to profit from his office (at least while he is in office), the obvious answer is "No." But we live in strange times where somehow Trump's actions are considered "maverick" or "draining the swamp," even though politicians throughout history have engaged in similar exploitations of office.