Nepal
Nepal is a fairly inexpensive place to visit, with most food, lodging, and transportation costsing only a few dollars if you eat, sleep, and travel locally. Nepal's street food does not have a good reputation. However, you may find inexpensive and wonderful home-cooked meals in small cafes run by locals. When booking your accommodation online, be in note that large businesses have taken over local homestays and converted them into boutique hotels and resorts. The "local guesthouses" you've reserved may be part of a larger hotel chain. When you arrive, you should book the first couple of nights online and hunt for accommodation from genuine local guesthouses.
If you decide to trek, as long as you do it independently and avoid climbing Mt. Everest, which costs tens of thousands of dollars, you can travel for as little as $10 per day on food and lodging at lower elevations, and closer to $20 USD at higher elevations on popular routes like the Annapurna Circuit.
Price: $28/day
Meals: $5 – $10 per day. Breakfast is available in several hostels.
Accommodation: $5-$10/ night in a local guesthouse
Transportation: $10-$15 per person for a private car and driver split between 4 people, or a local bus ride between cities
SIM card with data: $3 for 1.25GB with 30-day validity.