There are a few traits that Tom Walker and his wife share. First, they are both said to be extremely cheap and selfish. In the beginning of the story, the narrator states that "they were so miserly that they even conspired to cheat each other." Even though they are married, the two of them are so desperate to find and keep whatever they can that they actually try to cheat one another, an ironic and humorous point because they are married.
When Tom first meets The Black Man, or the Devil, he decides not to take the deal; however, when his wife hears of the terms, she decides to venture into the woods so that she can make her own deal with the devil. The text states, "Being of the same fearless temper as her husband, she set off for the old Indian fort towards the close of a summer's day." The reader sees here that, like Tom, his wife is not especially frightened of the Devil or the deal he is offering.
Probably the most obvious character trait the two have is linked to their selfishness and desire for money: both of them are willing to make a deal with the Devil. Both are willing to sell their souls to have money on earth without much thought for their afterlives. Money is the most important thing to each of them.