What are some exact quotations that show curley's wife being considered a property instead of a person?
It tells you a lot about the character that she's referred to, not by name, but by her relation to her husband. She is "Curley's wife," not a person in her own right. So right from the outset, we're left in doubt as to how she's regarded, not just by Curley, but by just about everyone else on the ranch. But in common with most of the ranch hands, Curley's wife has dreams. However, because she's nothing more than Curley's property, she hasn't been able to pursue her ambition to be a movie star:
"Awright," she said contemptuously. "Awright, cover 'im up if ya wanta. Whatta I care? You bindle bums think you're so damn good. Whatta ya think I am, a kid? I tell ya I could of went with shows. Not jus' one, neither. An' a guy tol' me he could put me in pitchers . . . "
And she appears to have dreamed of making it big in showbusiness for a long time, going right the way back to when she was a young adult:
"I tell you I ain't used to livin' like this. I coulda made somethin' of myself." She said darkly, "Maybe I will yet." And then her words tumbled out in a passion of communication, as though she hurried before her listener could be taken away. "I lived right in Salinas," she said. "Come there when I was a kid. Well, a show come through, an' I met one of the actors. He says I could go with that show. But my ol' lady wouldn' let me. She says because I was on'y fifteen. But the guy says I coulda. If I'd went, I wouldn't be livin' like this, you bet."
Curley's wife's resentment toward her husband comes through in the last line. "Livin' like this" is clearly something she can't stand. And who'd blame her? She's a kept woman; her life on the ranch, though materially comfortable, is mind-numbingly boring and restrictive. She hates her life and wants to escape; she wants to be an actress just like they told her she could be when she was fifteen—but she can't. Her whole identity is bound up in her tempestuous marriage.
In Steinbeck's Of Mice and Men, on page 94 of my copy of the book, Curley's wife tells Lennie why George says Lennie shouldn't talk to her:
She said quietly, "He's scared Curley'll get mad. Well, Curley got his arm in a sling--an' if Curley gets tough, you can break his other han'. You didn't put nothing over on me about gettin' it caught in no machine."
She adds a minute or so later:
"I get lonely," she said. "You can talk to people, but I can't talk to nobody but Curley. Else he gets mad. How'd you like not to talk to anybody?"
Curely treats his wife like she is a piece of property, like he owns her. He limits what she can do and who she can talk to--or at least he tries. She is kept on the property and told what to do.
Actually, however, the most important quote and detail that shows Curley's wife is treated with disrespect is the fact that readers have to refer to her as "Curley's wife," since she isn't even named in the novel.
I think that, overall, we see that Curley thinks that his wife is his property because of how he is always running around looking for her. He seems to expect that he has the right to know where she is at every moment. He seems to think that he owns her and that she should not go places without letting him know. You should also note that she doesn't even get her own name -- that implies she's nothing but his.
As for a specific quote, I would use one that is on page 62 in my book. This is where Curley and Slim are arguing. Slim is telling Curley that he should tell her to stay where she belongs. He is saying that Curley should control her better. That sounds more like someone talking about a dog than about a person.