So you go to a shop and see an ipod for 300. You know the same model can be bought from a shop 5-10 miles away for 200. What do you do?
Go to the shop 5-10 miles away.
Conclusion: It is well worth 100 to travel 5-10 miles to a different shop.
So you go to a car dealer and see a Ford for 25,000. You do a search and find the same model in a show room across town for 24,900. Do you go to the other dealership?
No.
Conclusion: It is not worth 100 to travel 5-10 miles.