Between Guadalajara and Lake Chapala the cost is about a dollar and a half. Destinations are scrolled on the front of buses, which travel every 10 or 15 minutes and keep close to schedules. Buses are crowded, sometimes hot, and seats are not always available. Americans don't seem to use buses much, but buses are economical and possibly more efficient than driving and trying to locate unfamiliar streets and neighborhoods while driving a car. If you use buses, you should learn as much as possible about schedules and destinations which are numerous but not confusing.
Buses are safe.
We rode them for two years constantly in Latin America without a problem. You can hail one en route, showing the number of fingers to indicate size of your party. Some taxi drivers speak English and provide valuable information. Most don't speak it, but will understand a little and estimate a price. Sometimes they have trouble finding the address, but if they do, they still stick by the quoted price.