Having been ostracized from the bunkhouse and limited in his participation with the other workers, Crooks, the sole black man on the ranch, is at first on the defensive when Lennie enters the barn. For,
He kept his distance and demanded that other people keep theirs.
When Lennie enters, therefore, Crooks bristles and tells the big man to get out of his room. However, the child-like Lennie expresses his loneliness; so, realizing the naivete of Lennie, Crooks allows him to stay and teases him about George's having abandoned him, but Lennie grows angry, so he stops. During this time, also, Lennie has talked about owning rabbits and a farm; however, Crooks ridicules him, saying that he has heard many a bindle stiff speak in this way, but "it's jus' in their head."
Just then Candy comes into the barn and as he approaches, Candy speaks to Lennie, explaining that he has been "figuring out about them rabbits." Crooks interrupts them, "brutally" mocking their dream. But, Candy swears that they will do it because they have the money "right now." Candy will not be discouraged and exclaims that everybody wants something that is truly his, not someone else's.
But we gonna do it now, and don't make no mistake about that....That money's in the bank....
Crooks asked, "You say you got the money?"
This is the first time Crooks has heard anyone say he has money for his dream. As he considers the reality of Candy, George, and Lennie's dream, Crooks asks hesitantly,
"...If you...guys would want a hand to work for nothing--just his keep, why I'd come an' lend a hand..."
Apparently, the mention of money makes the dream seem possible for Crooks.