Do children, ages 13 and 11, need to have an ISIC ID card in order to receive the student/children discounts (such as for the boleto turistico)? I assume not, but just wanted to double-check.
If you are planning on visiting several sites over more than 1 or 2 days, this is really the only way to go. Students 25 years and under and carrying an ISIC ID and chilren can buy the BT Estudiante for S/ 70. For Peruvian nationals, boletos are S/ 70 for the Boleto General and S/ 40 for the Boleto Estudiante.