My advice is clear and simple, don’t rush things, wait until you get to your hostel/hotel to purchase tours and transportation tickets. If you decide not to purchase tickets from your hostel, there are many tour agencies around Flores that offer competitive prices. An additional benefit of purchasing your tickets from a hostel or an agency is that unlike and individual, the hostels and agencies will still be there after you make your purchase. Take a walk, compare prices and strike a deal for a discount on the ticket prices.
Ah and one more thing – Beware of poachers like Enrique.
Have you entered Guatemala by bus? Did you pay an entrance fee? Have you ever been scammed in Guatemala? Leave a comment and tell others about it.