Why a subjunctive in this sentence?

Question

________ (Busquemos) un apartamento más grande para los cuatro.Why does this sentence need a subjunctive (as stated in the hint)?

Accepted Answer

Hola Ien
This needs the present subjunctive because it is a command to "ourselves", as in "let's ....":
¡Vayamos a la fiesta! Let's go to the party!
¡Bailemos todos juntos! Let's all dance together!
When you have a command/ imperative for the nosotros form, the form of the imperative is the same form of the present subjunctive. 
Here's the lesson for this.
I hope this clarifies it. 
Saludos

Answer

Thanks for your reply, Inma. At first I didn't understand the essence of the lesson on this, but thanks to your explanation, I do now!