Just be respectful.
Do not go to Sao Tome with an "I am better than you" attitude because you have money.
One of the few Americans who lived and worked there (the only African American EVER), I have seen my White countrymen enter Sao Tome with extremely arrogant attitudes. They come across as insincere and pretentious. They have no experience or appreciation in being around Black people. They have this ingrained attitude that because the people are largely poor, that they can talk down to them, yell at them and mistreat and disrespect them. Sadly, many of my White countrymen are in denial that they are being disrespectful as they feel "White is right." But the people know. So, please do not do that. Remember, you are in THEIR country and do not allow your dollars and dobras give you a sense of privilege and arrogance.