I've used LiveMe quite a bit, although I didn't end up wanting to make time for it in the end, at least for now. I'm saving Bigo for another time now that I'm more familiar with how these apps work.
The exchange rate for in-app currency is pathetic, but if you get enough attention you can definitely make some money that way. The gamification aspect of it can get certain viewers addicted. Watch some of the top streamers to see how they take advantage of that.
Most of the money I made, since I didn't stick around long, was from poaching viewers to other platforms, in my case I mainly used Snapchat. You will get a TON of private messages asking for outside accounts. And also for "open bobs".
I'd mainly suggest making an account and watching for a good long time before jumping in. All of the different currencies and games and contests and cliquey bullshit are confusing as hell at first.