It's $120/TB for the first 10TB in a month, so you need to be spending >$1200 just on bandwidth every month before you even get the "discounted" rates.
Vercel heavy user here. They have a very misleading pricing. It's "starting at $150", it varies depending on the region. I end up paying $400 / TB as we have a very international website.
In Singapore and Asia in general traffic is very expensive, because there are no peering exchanges. So you need to pay for each Mbps you use. Big ISPs there are oligopolies and aren't too fast or keen to work with you.