I think with most things the amount you can earn depends on how much you put in. There's certainly money to be made but it's never easy. You could make a lot of money from this forum if you've got the time and are willing to work hard.
Trading forex with btc I can make a lot per month, or at least a lot for me, which is roughly a low medium salary. It's not much but in my country life is pretty cheap so I'm ok with it and I'm sure that with more experience I'll do better and better

Where can you trade forex with bitcoin? How difficult is it to do?