Will altitude sickness ruin my trip?

Only if you rush. Fly into Lima (sea level), then take buses up gradually. Spend 3+ days in Cusco before attempting higher altitudes. Drink coca tea, avoid alcohol, and listen to your body.

Is it safe to travel alone as a first-timer?

Yes, but stick to the main backpacker trail: Lima-Cusco-La Paz-Uyuni. Hostels are full of other travelers. Avoid walking alone after dark and keep copies of documents separate from originals.

Can I really eat for $3-5 per meal?

At local markets, absolutely. A full meal with soup, main course, and drink costs $2-4. Tourist restaurants cost $8-15. Street food is $1-2 but be careful with your stomach the first week.

Should I book everything in advance?

Only your first 2-3 nights and Machu Picchu train tickets (5+ days ahead). Everything else can be booked day-of or next-day. Hostels rarely fill up except during Inti Raymi festival in June.

How to Backpack Peru and Bolivia on $30 a Day (First-Timer's Guide)

You can absolutely backpack Peru and Bolivia on $30 a day by staying in hostel dorms ($8-12), eating at local markets ($3-5 per meal), and using local buses instead of tourist transport. Book nothing in advance except your first 2-3 nights and your flight home.

Get your visa situation sorted. Americans get 90 days free in Peru, 90 days free in Bolivia. Bring 2 passport photos and $15 cash for Bolivia border fees. Keep your passport stamps - you'll need to show them.
Land in Lima and get out fast. Take the Airport Express bus to Miraflores district ($2). Stay 1-2 nights max at Pariwana Backpackers or similar ($12/night dorm). Book your bus to Cusco for the next day at Cruz del Sur terminal.
Head straight to Cusco for altitude acclimatization. Take the night bus to Cusco (22 hours, $25-35). Arrive and do NOTHING for 24 hours except drink coca tea. Stay at Loki or Milhouse hostel ($8-10/night). Don't book Machu Picchu yet.
Spend 4-5 days in Cusco getting used to altitude. Walk around San Pedro market, visit free museums, take the $2 bus to Sacsayhuamán ruins. Book your Machu Picchu train tickets online for 5 days later. You need this much lead time.
Do Sacred Valley on local transport. Take collectivos (shared taxis) to Pisac ($1.50) and Ollantaytambo ($2). Sleep in Ollantaytambo the night before Machu Picchu. KB Hostel costs $8/night.
Hit Machu Picchu the budget way. Train from Ollantaytambo to Aguas Calientes ($65 round trip), then walk up to Machu Picchu (1.5 hours) instead of taking the $24 bus. Entry ticket is $47. Bring your own snacks.
Bus to Bolivia via Puno. Cusco to Puno by bus ($8, 6 hours), then Puno to La Paz ($15, 5 hours including border crossing). The border takes 2+ hours - bring patience and snacks.
Explore La Paz and Uyuni. La Paz: Stay near Rosario Street, eat at markets in El Alto ($2 meals). Uyuni Salt Flats: 3-day tour costs $120-150 including transport from La Paz. Book with Red Planet or Quechua Connection.

Will altitude sickness ruin my trip?: Only if you rush. Fly into Lima (sea level), then take buses up gradually. Spend 3+ days in Cusco before attempting higher altitudes. Drink coca tea, avoid alcohol, and listen to your body.
Is it safe to travel alone as a first-timer?: Yes, but stick to the main backpacker trail: Lima-Cusco-La Paz-Uyuni. Hostels are full of other travelers. Avoid walking alone after dark and keep copies of documents separate from originals.
Can I really eat for $3-5 per meal?: At local markets, absolutely. A full meal with soup, main course, and drink costs $2-4. Tourist restaurants cost $8-15. Street food is $1-2 but be careful with your stomach the first week.
Should I book everything in advance?: Only your first 2-3 nights and Machu Picchu train tickets (5+ days ahead). Everything else can be booked day-of or next-day. Hostels rarely fill up except during Inti Raymi festival in June.