If you live that far from the store, with gas prices, wear and tear on your car and time driving to and from ... why don't you just order them online for Harbor Freight? The shipping is not the high. When the discussion was hot and heavy on this last year I couldn't get any of the blades locally, not even an hr away so I bit the bullet and ordered 20pks online.
Now that they are available again, I just might go and stock up, give some to friends as a surprise. The price is too good.