Fuel is cheap: it's $900,000 per Starship launch, according to Musk [0]. No disposable rocket comes within even a factor-of-10 of that.

[0] https://techcrunch.com/2019/11/06/elon-musk-says-spacexs-sta...

I was perhaps exaggerating a little with the fuel cost comparison, but we've had rockets like Astra R3 and SS-520 fly for under $5M per launch. Rocket Lab's Electron is ~$7.5M. That's all within a factor of 10.

fuel is cheap

most expensive part are the engines