Two temples in Ninh Binh. Bai Dinh Pagoda has 3 tickets and tours to book; Bich Dong Pagoda has 10 tickets and tours to book. The table and the two notes below put them side by side; the full pages have what to see, the ticket and the timing for each.
Bai Dinh is a huge pilgrimage complex rather than a single building, and entry to the temple grounds is free. What costs money is moving around it: the car park lies some distance from the main gate, and most visitors ride the electric carts that shuttle up to the entrance and back, paid as a return ticket. The great stupa at the top of the site charges a separate fee for its lift and viewing floors. None of this needs booking in advance.
Bai Dinh lies about 95 km south of Hanoi, so most international visitors see it on a day trip.
Bich Dong costs nothing to enter, so what is sold online is really a way of reaching it and of fitting it into a day among the limestone karsts of Ninh Binh. The tours that include it fall into a few clear types. The most common is a full day from Hanoi, about two hours away by road, which combines a sampan ride through the rice fields and caves of Tam Coc, the climb to the viewpoint at Hang Mua and a stop at the pagoda; lunch, an English-speaking guide, the boat ticket and air-conditioned transport are normally included, while drinks and tips are extra.
If you are already staying in Ninh Binh or Tam Coc, there are shorter local trips that start from your hotel.