To be honest it depends where you want to live within Brazil
There are many places to stay close to Copacabana beach and i will give you some examples. Because of the location there are numerous hotels as well as long term and short term rent options, all can be found by doing an internet search. You can pay as much or as little as you want for accommodation here.
When i have to go to Rio for a reason we will never stay on the front as the prices are just to expensive, but a few streets back they are quite reasonable. Just make sure there is some sort of parking available close by.
Word of warning in and around Copacabana beach, don't flaunt your wealth by wearing big gold chains and expensive jewellery as you will bring attention to yourself, which is what you don't want.
If you are thinking or permanently moving to Brazil and insist on Copacabana beach area then one of the apartments on the front will be right for you, but they are not cheap.
An alternative area is a place called Ipanema, which is a short drive away. There is a thriving expat community there.
Just be sensible wherever you are, and don't go out on your own.
This subject could go on for quite some time but throughout the site i have covered just about all angles, but if there is something specific you want me to go over then please just drop me a line and i will address it for you.