Is $50/day realistic in Bangkok?

Tight but possible. Hostels cost $12-18, street food $3-4 per meal, and transport $3-5/day. You'll have $15-20 left for activities and miscellaneous. Consider 3-4 days max in Bangkok on this budget.

What about the islands on this budget?

Very challenging. Koh Phi Phi and Phuket will break your budget. Koh Tao and Koh Phangan are more doable if you stay in basic bungalows ($12-15) and cook some meals. Budget $60-70/day for southern islands.

How much should I withdraw at once?

ATM fees are $5-7 per transaction regardless of amount. Withdraw larger amounts less frequently. Most ATMs dispense up to 20,000 baht ($550) per transaction.

Can I bargain at 7-Eleven and restaurants?

No. Fixed prices at convenience stores, restaurants with menus, and any place with price tags. Bargain at markets, with tuk-tuk drivers, street vendors without posted prices, and some guesthouses.

How to travel Thailand on $50 per day

Thailand is very doable on $50 per day if you stay in hostels ($8-12), eat local street food ($2-4 per meal), and use public transport. Your money goes furthest in northern cities like Chiang Mai and stretches less in Bangkok and the southern islands.

Choose your regions strategically. Northern Thailand (Chiang Mai, Pai) and northeastern regions are cheapest. Bangkok costs 20-30% more. Southern islands and beaches will push you over budget unless you're very careful. Plan 60% of your time in cheaper regions if sticking to $50.
Book hostel dorms, not private rooms. Dorm beds run $8-12 in most cities, $15-18 in Bangkok. Private rooms start at $20+ and will blow your budget. Book 2-3 days ahead through Hostelworld or walk-ins for better rates.
Eat where locals eat. Street food costs $1-3 per meal. Local restaurants charge $2-4. Tourist restaurants start at $8+. Look for places with plastic stools, Thai customers, and no English menus. Point at what looks good.
Master public transport. Local buses cost $0.30-1. Songthaews (shared taxis) run $0.50-2. Avoid tuk-tuks and private taxis except for airports. In Bangkok, use BTS/MRT ($1-2 per ride). Rent scooters in smaller cities ($4-6/day).
Plan temple visits and free activities. Most temples cost $1-3 entry. Many are free. Hiking, markets, and beach time cost nothing. Cooking classes ($20-30) and day tours ($25-40) are budget stretches but worth saving for.
Negotiate everything politely. Tuk-tuks, market goods, and guesthouse rates are negotiable. Start at 60% of asking price. Smile, be friendly, and be ready to walk away. Learning basic Thai numbers helps.

Is $50/day realistic in Bangkok?: Tight but possible. Hostels cost $12-18, street food $3-4 per meal, and transport $3-5/day. You'll have $15-20 left for activities and miscellaneous. Consider 3-4 days max in Bangkok on this budget.
What about the islands on this budget?: Very challenging. Koh Phi Phi and Phuket will break your budget. Koh Tao and Koh Phangan are more doable if you stay in basic bungalows ($12-15) and cook some meals. Budget $60-70/day for southern islands.
How much should I withdraw at once?: ATM fees are $5-7 per transaction regardless of amount. Withdraw larger amounts less frequently. Most ATMs dispense up to 20,000 baht ($550) per transaction.
Can I bargain at 7-Eleven and restaurants?: No. Fixed prices at convenience stores, restaurants with menus, and any place with price tags. Bargain at markets, with tuk-tuk drivers, street vendors without posted prices, and some guesthouses.