What do you really need to get started and how much will you likely end up spending (if anything!).
Being a "local" expert can be very profitable, and it's what most small businesses really want right now. You don't even need to live in the areas you serve!
It seems backwards, but focusing on on type of service or product will earn you more than trying to help everyone. (P.S. - "Small Businesses just Opening Up" is not a niche). "Divorce Lawyers" are a niche.