Yep, in smallish bulk (low 1000s), you can get them for about 10-20c a tag (and these are "self printed" ones you can print in-store as needed via dedicated RFID printers) (e.g. https://www.atlasrfidstore.com/rfid-label-4x2-for-the-zebra-...)

I am sure that amazon/walmart/tesco/whoever will need more than 1000 at a time and so obviously get a larger discount. Probably down to well under a penny or two - starts to make a lot of sense when you factor in the other benefits (lower staff, easier stock-tracking/taking etc)