Within Panajachel the easiest way to get around is on foot, but if you are carrying a load or just tired of walking you can flag down a taxi, or tuk tuk. They're everywhere and cost only 5 quetzales, or about 75 cents U.S., to get anywhere inside town. This is per person, so if there are 2 or 3 of you together, you can add up the cost. It's good to know in advance since if you're obvious tourists, the tuk tuk driver may double the price.
Our hotel provides free bicycles to guests, and although I'm nervous about riding a bike on these crowded streets, this is the main form of transportation for local families. As in the US, a husband and wife will each have their own car, in Pana they'll each have their own bike, some equipped with extra seats for carrying a child or two.
And there is the ever present chicken bus, the best way to get to Solola or other places inland. It's only 3 quetzales to go one way to Solola, a larger town than Panajachel. Many residents go on Friday when Solola has their big market day.
For all the villages around the lake, there's the extensive water taxi system. This is more expensive than a chicken bus, costing 25 quetzales per person to cross the lake.