If two or more people are trying to decide what to do or buy, use We could… or Shall we…?
We could go to another store?
We could ask them what they would charge?
We could ask his opinion.
We could eat out tonight.
Shall we ask for a refund?
Shall we come back later?
Shall we invite them to the party?
Shall we ask for his opinion?
Shall we consult a doctor?
To suggest what someone else can do or buy, use You could…
You could get that camera repaired.
You could ask his opinion.
You could transfer the money to his bank account.
You could wait till they return.
Use ‘How about…?’ if you have an idea about what to do or buy.
How about ordering a pizza?
How about eating out tonight?
How about inviting John to the party?
How about speaking to the manager?
How about changing the meeting to Friday?
Note that the verb form that comes after ‘How about…?’ must be in the –ing form.
Talking about your plans
Use I am going to… to talk about plans that you are sure of.
I am going to pay by credit card.
I am going to ask her out.
I am going to take a break.
I am going to throw a party.
To talk about things that you have just decided to do, use I’ll…
I’ll talk to the manager.
I’ll send the money today itself.
I’ll change the appointment.
To ask people about their plans, use ‘Will you…?’ or ‘Are you going to…?’
Are you going to rent that apartment?
Will you ask for a refund?
Will you get your money back?