Ask HN: Non-paying enterprise users vs. less paying users

I am currently starting up my first side project.

While it isn't my primary aim, I would like to figure out how I can get it valued to a suitable price and aim to sell in 12 - 18 months time.

I'm trying to figure out if I should aim for a high number of non-paying users or less paying customers.

What kind of metrics do potential buyers look at?