What is Tom's attitude before the bargain in "The Devil and Tom Walker"?
I think it is important to focus on what we are told about Tom Walker before he meets the Devil. It is clear that Irving doesn't present him as a paragon of goodness. Consider this description:
...there lived a meager, miserly fellow, of the name of Tom Walker. He had a wife as miserly as himself: They were so miserly that they even conspired to cheat each other... Her husband was continually prying about to detect her secret hoards, and may and fierce were the conflicts that took place about what ought to have been common property.
Note also how their plot of land and house is described - they live in a "forlorn looking house" which had an air of "starvation." There are a few, wispy trees, which are "emblems of sterility" and they have one "miserable" horse.
It is clear then that Irving is setting us up with a character who is so miserly and tight-fisted that he even tries to bargain with and trick the Devil - his attitude is very selfish and miserly, and thus he seems to be a fitting character to have a tussle with the Devil and in the end, lose, as he is dragged of by the Devil.
Tom Walker is an appropriate target for the Devil because he possesses the requisite vice that will eventually draw him to the bargain offered him.
First of all, Walker and his wife are tightfisted in the literal sense—they have fights:
The lonely wayfarer shrunk. . . at the horrid clamour and clapper clawing that he hears as he passes the forlorn-looking house.
In the figurative sense, Tom and his wife are tightfisted because they constantly "conspire to cheat each other." They are also very stingy; their horse is underfed, no smoke curls from the chimney of their home, and even their trees seem to be starving. Indicative, also, of Tom's greedy personality is his constant surveillance of his wife's activities and his contentious arguments with her over what should be common property.
When the greedy and spiteful Tom Walker seeks a shortcut one day on his return from a long trek, he finds himself on an "ill-chosen route" where, having stopped to rest at a fort, he meets "a great black man." Tom recognizes him as "Old Scratch" and listens as he is made an offer. He does not readily accept, though, because he is "determined not to do so to oblige his wife." After his wife's disappearance, however, Tom's now-unimpeded avarice drives him to bargain with the devil.