Most brokers offer a free demo account so you can try out their software. Note that modern broker software is a lot more than just execution software to enter buy/sell transactions. Modern platforms offer complex order types based on conditional logic. And brokers also try to distinguish themselves by offering free analysis tools. Ten years ago, analysis tools were largely separate. So approach your evaluation from both perspectives, analysis and execution. What's best for you depends on how you trade ... outrights, options, spreads, etc.