Your South African tax return will be cheaper than the US one. I don't think you would get a real person to do ths US part for under $250.
Your main expenses will be:
- The Forex fees when moving money abroad. Depending on who you use they always charge a percentage commission on top of the...
cguy answered most of your questions.
I would recommend speaking to a tax advisor before leaving SA. You want to make sure you have all your ducks in a row for the SARS process. I used Sable and they were great.
There are some tax practitioners in the US that used to be CAs in South Africa, so...