Is there a trial version of the live-trade plugin available?

No. As you might already know, all other modes of Jesse including the "import candles", "backtest" and "optimize" modes are free and open-source. In fact, even in the live-trade mode, Jesse uses mostly the same code of backtesting.

We also offer a free version of the live trading plugin which is great for trying out Jesse. Read the pricing page for more details.