If your an advanced user: Open-source trading bots such as Gekko[1] exist, whereas you can freely configure the software and implement in your strategies and indicators.
What guarantee is it that it will go property especially when it is going to go through the traders strategy and indicator? In percentage, what do you think can be represented in performance.
It's difficult, as what majority knows that using trading bot is not 100% guarantee, but if you will get use to it and your configuration on the bot is better as you continue to use it, then it your winning rate could increase. But using such as open-source trading bots are somehow useful compare to some trading bots that asking for a payment but the difference of it in the open-sourced trading bot is almost the same.
Most of these expensive trading bots are not worth buying if you will not optimize the use of it. So using the open-source is the best one when you are starting to learn about the tricks. It is still on the trader how can you maximize the potential of the trading bot. However, on my side, I still do manual trading so I know what's really going on with the particular coin. But some who have no extra time opt for trading bots.