Mr. Barkis is a cart-driver who brings David from his home village of Blunderstone, Suffolk, to Yarmouth, where the Peggottys live. Yarmouth is also David's gateway to London and the larger world, so David travels in Mr. Barkis's cart quite often once he starts school. Mr. Barkis develops marital designs on Peggotty because he knows that she makes amazing apple pastries (which we guess is...not the worst reason to want to marry someone). So he makes David carry a message to Peggotty: "Barkis is willin'" (5.33). This message makes Peggotty laugh herself half to death. Still, once Mrs. Copperfield dies and the Murdstones turn Peggotty out of the house, she decides it wouldn't be such a bad thing to marry Mr. Barkis.
For all of the humor that comes from Mr. Barkis's wooing, he and Peggotty have a strong marriage. Mr. Barkis is incredibly cheap, but he's saving all of his money so that he will have something to leave the Peggotty family, and his wife in particular, when he dies. As he's lying on his deathbed, he turns to Peggotty and tells her that there is "no better woman anywhere!" (30.72), which, we have to say, made us tear up. Mr. Barkis isn't really in the novel for much more than comic relief and a tearjerker ending, but he's a memorable character, for all of that.