It is very, very difficult to offer phone support as a solo developer, particularly at low price points (below e.g. $5k per year) and for low tech-literacy cust

It is very, very difficult to offer phone support as a solo developer, particularly at low price points (below e.g. $5k per year) and for low tech-literacy customers. You can still do it, if you need someone to talk to, you want to do customer development, or you have a customer who strikes your fancy for non-market reasons, but you probably should not message the expectation that you're available.