How much physical cash should I have for the USA?

Me and my fiancé are travelling to America next week for just over two weeks. We are travelling to Washington DC, Virginia, Baltimore, Philadelphia 🦅& New York. We have about £3,000 ($3,960) saved purely for spends on trinkets and food. All accommodation and travel is already paid for. We have a £2,500 spend limit credit card for security deposits at hotels and anything else we need it for. We have $150 in cash already but I feel like that’s probably not enough for tips and little purchases?

What do you guys think?