You will go broke if you pay to get into each museum, church, and archaeological site around Cusco [1]. Even if you are going to visit only a few places, buy a boleto turístico for US$45 (US$24 for students under age 26 with ISIC card). The ticket covers 16 sites in and around Cusco, including must-sees like Sacsayhuamán [2], Pisac [3], and Ollantaytambo [4], and you cannot actually get into a lot of the sites if you do not have the ticket.
The tickets can be bought at the entrances to most major sites or at COSITUC (Av. El Sol 103, #102, www.boletoturisticocusco.com [5], 9 a.m.–5 p.m. Mon.–Fri.).
Unfortunately, the pass only lasts 10 days. There is a process for extending expired passes, but—take it from us—it’s not worth wasting a day navigating the halls of the Instituto Nacional de Cultura, which is a harrowing bureaucracy even by Peruvian standards.
The ticket covers these 16 sites:
The Coricancha temple [14] (US$3.50) and the Museo de Arte y Monasterio de Santa Catalina [15] (US$2.50) are not included in the ticket, but if you go to both you only pay US$5.
The Catedral [16] (US$8.50), Iglesia de la Compañía [17] (US$3.50), Iglesia San Blas [18] (US$5), and the Museo de Arte Religioso [19] (US$5) are not covered either, but if you plan to go to all four you can buy the boleto religioso at the entrance of any of these sites for US$17 (US$8.50 for students under age 26 with ISIC card).
Other interesting sites not included are the Iglesia de La Merced [20] (US$2), Museo Inka [21] (US$3.50), and the Museo de Arte Precolombino [22] (US$7).
Links:
[1] http://www.moon.com/destinations/peru/cusco
[2] http://www.moon.com/destinations/peru/cusco/sights/outside-cusco/sacsayhuaman
[3] http://www.moon.com/destinations/peru/the-sacred-valley/pisac
[4] http://www.moon.com/destinations/peru/the-sacred-valley/ollantaytambo
[5] http://www.boletoturisticocusco.com
[6] http://www.moon.com/destinations/peru/cusco/sights/southwest-the-plaza-de-armas/plaza-regocijo
[7] http://www.moon.com/destinations/peru/cusco/sights/east-the-plaza-de-armas/museo-de-sitio-coricancha
[8] http://www.moon.com/destinations/peru/cusco/sights/outside-cusco/q-enqo
[9] http://www.moon.com/destinations/peru/cusco/sights/outside-cusco/puca-pucara
[10] http://www.moon.com/destinations/peru/cusco/sights/outside-cusco/tambomachay
[11] http://www.moon.com/destinations/peru/the-sacred-valley/pisac/sights/chinchero
[12] http://www.moon.com/destinations/peru/cusco/sights/outside-cusco/tipon
[13] http://www.moon.com/destinations/peru/cusco/sights/outside-cusco/rumicolca-and-pikillacta
[14] http://www.moon.com/destinations/peru/cusco/sights/east-the-plaza-de-armas/coricancha-and-santo-domingo
[15] http://www.moon.com/destinations/peru/cusco/sights/east-the-plaza-de-armas/museo-de-arte-y-monasterio-de-santa-catalina
[16] http://www.moon.com/destinations/peru/cusco/sights/plaza-de-armas/catedral
[17] http://www.moon.com/destinations/peru/cusco/sights/plaza-de-armas/iglesia-de-la-compania
[18] http://www.moon.com/destinations/peru/cusco/sights/northeast-the-plaza-de-armas/san-blas
[19] http://www.moon.com/destinations/peru/cusco/sights/northeast-the-plaza-de-armas/museo-de-arte-religioso
[20] http://www.moon.com/destinations/peru/cusco/sights/southwest-the-plaza-de-armas/iglesia-de-la-merced
[21] http://www.moon.com/destinations/peru/cusco/sights/northeast-the-plaza-de-armas/museo-inka
[22] http://www.moon.com/destinations/peru/cusco/sights/northeast-the-plaza-de-armas/museo-de-arte-precolombino