Austen introduces the reader to a world of characters who represent both aspects of the title, pride and prejudice. The whole plot revovles around the different character's attitudes that creates the conflict in the story.
Elizabeth Bennet represents both pride and prejudice, for example her pride instructs her to reject Mr. Collins proposal of marriage based on the fact that she feels that he is not a suitable candidate for her. Her prejudice towards Mr. Collins, who really is a typical man of the period, and who holds the keys to the future of her family home, represents the answer to one of the Bennet family's biggest problems, being put out of their home in the event of Mr. Bennet's death before one of his daughters is married.
So Elizabeth's rejection of Mr. Collins is an example of both characteristics. Elizabeth continues with her attitude toward Mr. Darcy a man that she judges to be very prejudiced in his views towards both her and her family.
Elizabeth and Darcy both suffer from pride because his demeanor gives off a vibe of superiority which is interpreted angrily by Elizabeth who sees Mr. Darcy as a pompous, arrogant aristocrat who believes he is better than everyone else.
"His pride," said Miss Lucas, "does not offend _me_ so much as pride often does, because there is an excuse for it. One cannot wonder that so very fine a young man, with family, fortune, everything in his favour, should think highly of himself. If I may so express it, he has a _right_ to be proud." "That is very true," replied Elizabeth, "and I could easily forgive _his_ pride, if he had not mortified _mine_."But I can assure you," she added, "that Lizzy does not lose much by not suiting _his_ fancy; for he is a most disagreeable, horrid man, not at all worth pleasing. So high and so conceited that there was no enduring him! He walked here, and he walked there, fancying himself so very great! Not handsome enough to dance with!" (Austen)
Mrs. Bennet is also prejudiced towards Mr. Darcy, in the above quote, she is explaining his behavior to her husband.
Mr. Darcy is prejudiced toward the Bennet family, he finds them to be less than worthy individuals, they are loud, Mrs. Bennet talks too much, her daughters do not follow the behavior that polite society requries of them, he sees them as wild.