Harriet spent all day in a new york office after asking for $20.00. at the day's end she received $60.00. why did she need the money

Assuming that you're talking about Harriet tubman the abolitionist, 

Back then , she experienced some sort of illness on her brain.

She really need some money to get into brain surgery procedure

It can provide a social code to protect each citizen's future economical earnings. and then obviously defending the country from invading countries.