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Comment by cobookman | Hacker News Reader

How much per item do you pay for cashier staff though. Might be the same as the tag cost. Also in regards to RAIN RFID tags vs dumb print tags yep you are talking about a 5 cent increase. But you also lift inventory accuracy from ~70% to 99.9%.

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This seems easy to estimate. At my local large suburban supermarket doing weekly shopping for a hungry family I have a receipt with the last line listing "53 items". So at 5 cents per tag, that's $2.65 of tags ending up in the landfill per week. The cashier takes less than 5 minutes for the entire transaction including scanning and payment and small talk, so (5/60)*7.25 = about 60 cents. Now cashiers are not 100% busy and get breaks so I would round the ratio down to RFID is currently about 3 times more expensive than human.

Of course a cashier can supervise up to 16 self checkouts in a low crime demographic area, so add in a new factor of 16.

For people who don't care about cost and scoff at $2.65 per visit, for a mere $9.95 they deliver...

Tags used to be 60 cents. Now 5 cents. If they got used for masses of things e.g. groceries, they'd go down to a negligible cost. Folks like WalMart can actually drive this themselves.

Walmart already uses RFID in the backroom and for palettized loads, but not for stock that customers handle.

In my own work with RFID, the main problem we have is (after disregarding the cost of the transponders) is getting someone to put a transponder sticker on every single widget - stores already stopped using those "pricing guns" when they adopted UPCs/EANs, they don't want to regress backwards.

The solution is universal adoption of the EPC RFID system, but that requires all suppliers and logistics infrastructure to also adopt it. It's happening... just very slowly.

If they got really cheap, you could imagine 'spraying them on' a pallet and then wanding each item in. Combined with a simultaneous read of the RFID tags that 'stuck', and presto. Just brainstorming.

If they're using serialized EPCs (which track a unique item, not just SKUs) then this won't work because need to ensure each physical item is uniquely tagged, and that two tags with different serial numbers aren't on the same item (though duplicate tags with the same serial are fine) and that no two items have tags with the same serial.

If they're using non-serialized EPCs (so just logging SKU) then they need to ensure exactly 1 tag is on each item - no more and no less - otherwise inventory counts will be inaccurate.

Unique tag serial numbers would work fine. No duplicates (don't even understand how that would happen). More than one tag not a problem (enter one or all; whatever, as long as scanning later identifies the one item).

You still need some staff, sometimes items are damaged, the item doesn't scan, the payment won't go through, the customer changed their mind etc etc. You can't get rid of all staff.

A cashier can process tens of thousands of items per hour, at a wage of under $15 per hour. This means that the cost of a cashier can be around 0.1¢ per item sold for a busy store

Generously assuming a cashier can check one item a second for an hour, he can check only 3600 items. "Tens of thousands" seems off by at least an order of magnitude.

I was thinking of some costco cashiers I've seen, and they do far more than one item per second. That said, when you consider the downtime of processing the transaction, your estimate is probably not too far off. It makes the low end cost of transponders comparable, though just.

You can just replace them with self-checkout. You still need some cashiers (as you would with RFID) and don't have the cost of extra tags.

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