It's still a valid observation though. People don't drive to another store to save 10 dollars on a 500 dollar couch but they will drive all the way across town

It's still a valid observation though. People don't drive to another store to save 10 dollars on a 500 dollar couch but they will drive all the way across town to save 10 cents a gallon on gas. This isn't rational: they're clearly not buying the 100 gallons of gas for the gas-drive to make sense.