No extra expense for the tax payer for the medical staff. Those doctors, nurses, and corpsmen are paid whether the president is there or not.
The medication Remdesivir is probably the biggest cost. If it’s received as an experimental drug it should be paid by research dollars, but probably it isn’t. Same with the antibody treatment. Those would be what we need to research, how much was paid for that.
Everything else in his care isn’t very expensive. It’s all at cost all the xrays, bandaids, gauze, etc. The X-ray machine is already there, there isn’t a charge per X-ray it’s just the electricity used to do the X-ray. The radiologist is salaried just like the rest of the medical team. Maybe they pay a laundry service at full retail for the bed linens and gowns.
Edit: @janbb’s article says about $2k to $3k for the Remdesivir.