In the past there were two bots I used, QTL and Trader Daddy. I liked these bots as they just required holding some coins and not some purchase or fee. Also, easy to use and not some command line system. QTL is no longer under development and I would not use it, not even sure if it is safe. Trader Daddy I hear is coming out of Beta soon, who knows. The requirement to use it is 500 RBY on Trex. I used the old version ages ago and it worked well. If you do decide to use it, at your own risk, and I would not do it with tons of crypto on the exchange, and I would certainly not enable any arbitrage functions. The RBY devs have been working on the project for years so it should be fine. Anyway, you need 500 RBY held on an exchange. Up to you, but I picked up enough RBY to use the bot and might use it, but only with limited funds, not some huge portfolio sitting on an exchange. Just in case.
Trader Daddy is a scam.