At your service
A very common and polite alternative, literally meaning 'To serve you.' Often used in customer service.
Means 'at your command' or 'at your order.' Very common in many Latin American countries, especially in shops and markets.
This is a question: 'How can I help you?' It serves the same purpose of offering assistance.
Welcome to our hotel. We are at your service 24 hours a day.
If you need anything else, just call. At your service.
The vendor at the market told me: 'Come in, at your service!'
Hello, good afternoon. How can I help you?
'A su servicio' and 'Para servirle' are the standard, formal phrases understood everywhere.
'A la orden' is extremely common here, used by vendors to attract customers and to respond to 'thank you'.
'Para servirle' is very frequent. You will also hear 'A sus órdenes', which is a very polite variation of 'A la orden'.
'A su servicio' is understood but can sound very formal or even a bit old-fashioned. It's more common to hear service staff say '¿En qué puedo ayudarle?' or simply 'Dígame' (Tell me).
Like in Spain, 'A su servicio' sounds quite formal. People are more likely to use a direct question like '¿En qué lo/la puedo ayudar?' (How can I help you?).
Using 'a tu servicio' in a formal setting. — 'Tu' is the informal 'you'. In most service situations (hotels, restaurants, shops), you should use the formal 'usted', which corresponds to 'su'. So, 'a su servicio' is correct for showing respect to a customer or stranger.
Saying 'por su servicio'. — This is a direct translation of 'for your service' but is incorrect. 'Por' would mean 'because of' or 'in exchange for'. The correct prepositions to offer service are 'A' (A su servicio) or 'Para' (Para servirle).
Using 'A la orden' in Spain. — This phrase is a strong Latin American regionalism. While a Spanish person might understand it from movies, it is not used there and would sound out of place. Stick to '¿En qué puedo ayudarle?' in Spain.