I would argue that a grocery store is a combination store and marketplace in that case. Stores have plenty of in-house brands, they also have racks of goods that are stocked and sold by third parties wherein they get a cut.

To be fair, I think I would be more comfortable comparing Amazon to Sears in it's heyday.

>, they also have racks of goods that are stocked and sold by third parties wherein they get a cut

I'm sure that exists, but it's not common. Grocery stores often charge slotting fees, but that's not the same as renting shelf space--the store still owns the product (even if there is an agreement to buy it back if it doesn't sell).

Also retail stores take on more product liability than marketplaces like flea markets do.

What store / grocery store has goods stocked by third parties? (Rather than purchased from the third party by the grocery store)?

All of the ones around here do. Used DVD racks still exist. Soft drink vending machines. Seasonal items. Newspaper racks.

In the case of items actually run through the register, I'm not sure how that's dealt with from an accounting standpoint. I do know that the stores have the ability to return 100% of unsold goods in those cases.