I got a Barnes and Noble gift card for my birthday. I was sad to see that old Nancy Drew paperbacks cost $6 on B&N, when they cost $4 on Amazon.
However, on both websites, Simon and Schuster charges $6 for the eBook versions of the old Nancy Drew books. That makes way more sense now! On Barnes and Noble, they are price matching. The eBook costs just as much as the physical book does. I would totally buy the eBook version, to help save the environment (and to get the books quicker!).
On Amazon, though, the eBook is $2 more than the physical book, so it does NOT make sense to buy the eBook version. I would totally buy the physical version, to help save money (and to get the resale value!).