Chris Koerner writes…
The business: mailbox installation and repair 
Chris references a 2-year-old comment on Reddit…
I did an entire neighborhood last year. I fixed, straightened and painted a total of 23 mailbox stands. I charged $9k. I had it done in about a week. I had to replace 2 stands completely that held 6 mailboxes too. You can make really good money.
$9K for 23 mailboxes sounded excessive to me at first 
but not by Chris’ math…
Let’s say you live in a city with 100,000 people. Standard mailboxes need replacement about every 10 years. That means 5,000 mailboxes in your area need work every year.
If you capture just 5% of that market at $500 per job, that’s $125,000 in revenue…
There’s a massive opportunity here that almost no one is talking about.