How much will it cost to travel to america for three weeks?

Blomkest I am planning to travel to America for 3 weeks going to 3 states New York, Boston and LA, I am travelling from the UK does anyone know how much it will cost and what's the best amount of money for spends to take with me. Rutledge NY, Boston and LA aren't cheap you need about $300-500/day for lodging, food, trans and misc expenses. Have a great trip. Avalon Airfare will be your biggest expanse and the costs are so varied it's impossible to estimate until you sit down to purchase your tickets. A flight from NY to LA could cost you $200 or it could cost you $1400. It just depends on when and who you fly with. Assume that any cross country airfare will cost you $500 or more. Lodging in a decent hotel will be close to $250 a night in NYC. Slightly cheaper in LA and Boston but not by much. Daily expenses for food and entertainment and ground transportation (taxi and public transportation) will average $100 a day. So you are looking at spending $300 a day for food lodging and entertainment expenses for 21 days. That's $6300 without the airfare to get you from city to city. Plus you have to consider the International flights from the UK. I think you could easily be looking at a $10,000 USD trip.