It's important to understand that TradeZella is a journal for analyzing your real trades after you've taken them, while FX Replay is a simulator for practicing before you trade live. They serve different purposes and are often used together. However, TradeZella ($29-$49/month) offers best-in-class replay of your actual executed trades, integrated with powerful performance analytics and prop firm sync, making it an indispensable tool for live traders seeking to improve their results.
The platform routinely offers a limited free trial for new users to test the interface, features, and speed before committing financially.
For traders using standard desktop platforms, MT4 and MT5 include a built-in, local backtesting engine. 100% free.