Re: IPv4 smaller than /24 leasing?

On Thu, 04 Jan 2018 17:40:27 -0500, Justin Wilson said:

I know of dozens, if not hundreds of small ISPs that can’t participate in BGP because they don’t have big enough blocks.

What's the business model, if you have less than 120 customers? Selling value-add services on top of moving the packets? Or just be in a country where cost-of-everything is so cheap that you can make a profit on 120 customers at $20/mo? And hundreds? Is that "in the US", or "worldwide"?