Long time ago I used to know this guy that collected blood from slaughter houses and sold it to medical testing companies.
Tens of gallons per day.
Show up at the slaughter house, collect the blood as it's being drained from the animals, deliver to the companies, get paid.
One owner/manager and one collection/delivery guy.
Setting up a business nowadays in the states is difficult.
Tons of licenses, regulations, etc.
I saw a documentary about a lady who started her own transport company.
Her clients were poor relatives of prison inmates.
She'd pick 'em up, bring to visit and take 'em home.
But she got shut down as she needed to get a license from some board.
And since the board was made up of friends of her competition, she got shut down.