Let's Go
Use this to mean 'Let's leave' or 'Let's get out of here.' It's slightly more emphatic about departing a place.
A common and slightly softer way to suggest leaving, framed as a question: 'Shall we go?'
A very common, informal way to say 'Okay, let's do it' or 'Let's go' when agreeing to a suggestion.
The class is over. Let's go!
It's late now. Let's go home.
I'm tired. Shall we go?
Should we go to the park? — Let's do it!
'Vamos' and 'Vámonos' are universally understood and used. 'Dale' is also extremely common as an affirmative response meaning 'Okay/Let's do it.'
'Vamos' and 'Vámonos' are standard. You will also frequently hear 'Sale' used just like 'Dale' to mean 'Okay, let's go.'
'Vamos' and 'Vámonos' are the most common phrases, same as in Latin America. 'Venga' is also used often to mean 'Come on' or 'Let's go.'
'Vamos' is standard. 'Dale' is used constantly to agree to something, including the suggestion to go somewhere.
'Vamos' and 'Vámonos' are standard. 'Dale' is very common. You might also hear 'Listo, vamos' which means 'Okay, let's go.'
Using 'Nos vamos.' as a suggestion. — 'Nos vamos' is a statement meaning 'We are leaving.' To make it a suggestion, you need to say '¡Vámonos!' (command) or '¿Nos vamos?' (question).
Saying 'Vamos a ir.' to mean 'Let's go!' — 'Vamos a ir' means 'We are going to go.' It describes a future plan, but it isn't used as a command or suggestion to leave right now. For 'Let's go now!', just use 'Vamos'.
Confusing 'Vamos' and 'Vámonos'. — They are very similar. Use 'Vamos' as a general 'Let's go' (e.g., 'Vamos a la tienda' - 'Let's go to the store'). Use 'Vámonos' specifically when you mean 'Let's leave this place' (e.g., 'Esta fiesta es aburrida. ¡Vámonos!' - 'This party is boring. Let's leave!').