During the sequence at Sam's house at night, Dwight puts the pitchfork up against the counter facing one direction. However, during the scene at the end of the film, the pitchfork is leaning the other way around. There is no way the pitchfork could have been moved as the house remained undisturbed after Dwight left it.
When the main character returns some empty cans for money we see several cans returned. While the deposit ticket (briefly) only states 20 cents and wouldn't be enough for most purchases, let alone the map he buys, he simply had other loose change he had scavenged.
When Dwight stops at the diner to inspect the parked cars, he tests the handle of the Chevrolet truck. The door is supposed to be locked, he goes on to bust the window out. However, when he tests the handle, the door opens a little bit, thus revealing that it wasn't locked in the first place.
When Margaret Gaffney asks Dwight if he's in a rush, the stove clock behind her reads 8:26. Two shots later it reads 8:32 despite the fact that almost no time has passed within the film.