Let me describe the complete cost breakdown of a 3-week solo trip through the Peruvian highlights circuit because the variance is significant depending on your choices.

Lima (3 nights): accommodation in Miraflores (safer, nicer, tourist-friendly) runs $18-25/night for a hostel dorm. The historic center is worth a day and is free. Peruvian food in Lima is genuinely extraordinary — ceviche at a local cevichería costs $6-10 and is better than what you get in most of the world at any price.

Cusco (5 nights including acclimatization day): hostel dorm $12-16/night. The Cusco tourist ticket covers most major sites around the city and the Sacred Valley ($70 for the full ticket, valid 10 days). The acclimatization day is non-optional — plan to do nothing strenuous on day 1 at 3,400m.

Machu Picchu: train from Ollantaytambo to Aguas Calientes $30-50 return (book well in advance). Site entry $45-60 depending on the zone. Bus up from Aguas Calientes $24 return. Total for the Machu Picchu day: $100-130. This is the one unavoidable expensive day in Peru.

Arequipa (3 nights): often skipped but worth it. Hostel $10-14/night, the city is strikingly beautiful, the food (queso helado, rocoto relleno) is excellent.

Lake Titicaca (3 nights): Puno as base, $12-18/night. Island tours to Uros (floating reed islands) and Taquile cost $15-25 with a local guide.

Total for 21 days: approximately $900-1,100 including Lima to Lima internal flights. Machu Picchu is the cost anchor — it's non-negotiable and genuinely worth every cent.