If you're still new with Forex, 200$ is good. But I recommend you have a proper money management, set a goal to grow $200 into $500 as example.
I agree with you, if a trader starts with low investment and keeps a low target of profit then he can grow his account steadily but if he tries to grow $200 in $600 over night, then he can face margin call as well.
even if you have a great experience on demo account and feel that you are ready to trade real money, it's better to start with less input. There will a lot of time to put more money. And live trading and demo are not the same. 200$ is good for the start, but don't think that tomorrow these 200 will become 500)
The point is that trading with 0.01 lot and 200 dollars deposit is a waste of time. You came there to earn and earn higher than you can get in regular office job. Its good if you have several sources of income so there is no pressure from wasting time studying trading, but when time presses then you also need to remain in balance psychologically.You can adjust the lot size according to any capital you have in your account. So $200 or $2000 or more, if you can adjust your money management, you can trade any amount possible.