One user there already correctly noted that success in Forex as an additional source of income depends on three things.
First, it's your free time, only if you have enough time, you will be able to devote it to trading and learning.
Second, it's your finances. No, with $100 you will not be able to enter the market and earn enough money, you really need enough money.
Three, these are your skills. They can be improved and trained, but they're still important and their mastering requires a lot of your time.