It's only 50 cents and it saves you time and gas. Our guides both ways were very nice and didn't talk too much or be rude like previously stated. The only thing that annoyed me a bit is that there's signs everywhere at the trolley stations in PF saying that the ride to Gatlinburg would be 50 cents as well, but it's not. It's 75 cents to get to the welcome center, and then another 50 cents to get to the Ripley's. They also told me that I couldn't walk from the welcome center to Gatlinburg since it's a National park.. Next time I'm just going to walk anyways :P
Overall, I will use the trolleys in both PF and Gatlinburg whenever I need it! It's the best value honestly.