Given recent reports that President Trump’s condition was actually worse than originally reported, and the fact that he himself called his monoclonal antibody therapy a miracle drug, it seems these should be much more widely available.
To answer the original question, most of the cost estimates I’ve seen ranged from $1,100 - $1,500 per treatment. So not cheap, at least not today. But a basic VCR cost $1,000 or more when new at one point too.
That’s the cost of aspirin compared to a stay in the ICU.
Perhaps the supply is limited? I can’t imagine cost being a factor. But then again, bureaucrats, so there is that.