You look like an understanding fella. You know how it is. Sometimes you just can't get all the dough. Next month for sure.
Oh gee, I must have left my wallet at home. Well I have a little money with me, I'll bring the rest next month. Trust me.
I really am quite sorry about this, but I just can't seem to raise all the necessary funds. I'll be back next month for the rest. You can depend on it.
I fear that I cannot take it all this month.
Have no fear. Next month I will be able to take complete delivery. But this month I cannot.
Due to bad weather, my funds have not arrived from Tunzankipital. I will pay what I can. Please hold the rest.
Will you please hold some of it till next month.
I am afraid I can't accept a complete shipment this month.
