There are two main types of automated trading. Systems which benefits from market differences in m secs, and strategies using a higher timeframe.
1) For Hfreq trading you need the tick data before the market, you need to pay to get the tick 100ms before the others, plus the ability to execute orders at a range of brokers. The system requires a set-up no individual trader can match.
2) Higher timeframe trading, typically pairs trading, if the timeframe is above lets say 60 minutes charts, no need for automated trading. Thus automated trading for individuals is for daytrading typically 1 - 5 minutes charts. To develop a strategy, backtest this, run and administrate such is quite a job.
Ask if anybody here is using unattende automated trading, and if they have succes - ask them how much work it takes to develop - and how much work it takes to administrate and run.