First, I would like to understand better how they work, anyone has a good recommendation?
Which one is the easiest one to use? I found this one: Haasbot 2.0, but it seems a little complicated , and another thing is that I don't understand how they charge, and I am kind of skeptical about scams.
where announcement thread hasbot in bitcointalk
if in bitcointalk trading bot popular is GUnbot, maybe you can visit gunbot announcement thread and read in there