Couple quick clarifications:
BFR isn't a name that's still in use. Poster you're responding to was correct in calling it Starship: "SpaceX's Starship spacecraft and Super Heavy rocket (collectively referred to as Starship)" (from https://www.spacex.com/starship).
Starship projects to be significantly less expensive than Falcon Heavy _or_ Falcon 9. With total reusability of both stages and a construction built toward little to no refurbish or rehab, the cost per launch is nearly completely dictated (order of magnitude) by fuel costs, and project to be ~$2 million. This is an order of magnitude reduction in $/kg over the Falcon 9.
https://www.space.com/spacex-starship-flight-passenger-cost-...