Will imagration call you from Ghana about how much money a person needs to travel to the USA

No, first immigration does not call.
Next there is no amount required to travel.

Sounds like someone is or is trying to scam you.

Ah Ghana, the scam capital of the world.

Immigration won't call you, a scam artist pretending to work for immigration in order to get you to pay money that isn't required, will call you.

US doesn't require a certain net worth for an individual to travel.

You're being scammed.

Sure they will call. This "Government official" will be the brother of the scammer. Never read about Ghana scams? BUT WAIT-let me have your phone number and bank account with PIN and I can do it for you at no charge, save you a lot of trouble. I have a third cousin, twice removed, who has a friend who knows someone that has a friend that does this all the time. NOT!!! Don't even think of doing it. XMAS is a favorite time-"I'd love to see you but I spent all my money on my sick mother".

Ah yes, the sick mother, or they need to pay the government a certain amount of money to be allowed to travel abroad, or the country they're travelling to is demanding a certain amount of money in the bank before they'll let them in. Then you send the money and ask when they're coming, and they suddenly need more money that the government didn't tell them about, or they had an accident and need money for the hospital stay and meds, and then their mother or brother or sister was in an accident, and then they need to pay off a loan, or taxes, or something. You'll never ever see that person, and truth is, that person doesn't even exist. The gorgeous woman that sent you her photo, the girl you thought you were talking to all these months, is actually a 30 year old guy in a room with 100 other guys scamming people all over the world.

Seriously, just Google Ghana scams. Ghana is the scam capital of the world, famous for their online scams.

Give them your bank card, your check book... and everything you have.. it won't be enough and you won't ever see this scam artist. You've been played for a fool by African con artists.