I'm only looking

I'm only looking.

 and I'm just looking.
I am not a buyer, I am only examining your merchandise. (A phrase said to a shopkeeper or clerk who asks May I help you?) Clerk: May I help you? Mary: No, thanks. I'm only looking. Clerk: May I help you? Jane: I'm just looking, thank you.
See also: look
References in classic literature ?
"I don't mean any harm," he said, when I turned round on him, "I'm only looking for my master." The tones in which he spoke betrayed unmistakable fear.