I buy from AMZN, but have bought more from Wal Mart. That said, only one online purchase from Wal Mart, multiples occasionally from AMZN. Last thing I purchased from AMZN were replacement batteries for a cordless drill six months ago. So Prime membership has never been an economical route for our family. I have actually had better luck on the things I purchase going to Best Buy, Home Depot, or Lowes online. Then again I am not an electronic aficionado. Last online purchase three weeks ago from REI to patch a backpack air mattress. The wife purchases more online then I do, predominantly from clothing retailers, but those are direct.
One thing I have noticed is more repair parts going to the big boxes. For example, I need a grill replacement part that I bought from an online vendor in the past. This time found it cheaper at Home Depot. I would imagine with the economy tighter there is more demand for repair then replace.