Both free and paid versions of TradingView give real-time data, and you can use both for trading. However, you cannot use continuous alerts in Free version. Once you set an alert, it will trigger once and then disable automatically. Also, you cannot set more than two types of alerts.
We suggest you to use Free trading view version to test out system trading.
Then, move to one-month free trial of paid version. This gives you enough time to get settled in trading.
Then, finally, start trading with the paid version of TradingView.