I find myself doing that too. double :smack:
I believe that some experiments have been done with totally irrelevant numbers - like the last three digits of your social security number. But others have been done in this way, and we didn’t want to make it all that obvious.
The numbers were so out there (like the Chicago mean temperature I mentioned) that I doubt we were steering anyone. But it was also a motivator, not a scientific experiment - n was way too small to make the results particularly significant. (Though they were better than my daughter expected them to be.)
The 4 for $6, save $1.16 - $1.79 singly operation is standard practice in Australia also. One or other variety of tuna is sold like that at Woolies pretty much all the time.
I’m blown away.
Stores here(Michigan) always do “10 for $10” and the 11th one is free. That’s how they get you to buy more stuff. Most people wouldn’t have bought 10 items, so they will buy 10 items to get themselves the 11th one free.
Otherwise, there is no point to 10 for $10.
I worked at a gas station in the US where there’d be multi-item discounts. Say 2/$2 20oz pepsi products instead of 1.19 each. The way it works is that we'd have to scan the 2 items and then enter a discount code that would take away the extra .38. It would still ring up as $1.19 each until the discount was applied.
Which left me in the position of wondering, whenever I saw a X items for $Y, if it was like that system or just meant every unit was discounted. So there are definitely examples in the US where you have to buy the certain amount to get a discount - which might lead to people who are unsure of which method they’re using to just buy however many items it suggests.
Really, it’s kind of unfair not to mention in small print on the advertising which method it means.
Unless the owners/managers wanted it to be done that way, it sounds like a primitive POS application - most can handle that sort of pricing automatically without needing to enter a discount code.
If the advertising says only x for $y, then there is no bulk discount and you can buy one for the same price. If the price for one is higher, then they have to state that.
The oddest one to me is buy-one-get-one-free offers, which strongly suggest that you pay full price for the first and nothing for the second, yet if you just buy one you get it for half price. The stores could do it either way, but for some reason around here the stores choose the “both at half price” way.
There was a post on the Sociological Images blog while back (I’m on my phone right now so I can’t look for it ATM) that was related to this; it discussed the appeal of discount stores like tjmaxx and marshall’s, and how the marketing totally makes people just BELIEVE the merchandise will be a good deal. Things like the tag shows the original msrp as $89.99 but omg!!! Tjmaxx is selling it for just $39.99! In actuality, there’s no evidence/law that says it EVER sold for that msrp; the S stands for “suggested”, after all. 
The technique I found facinatingly slimy was the “compare at” tags. In this case there was no msrp, no “official looking” price tag, but they’ll have COMPARE TO $89.99 underneath their price of $39.99. But… There’s nothing to really compare it to! They are carefully NOT stating that it has sold for $89.99 anywhere, ever. And since some of the labels there are actually made specifically FOR the store, the item may never exist in any other store. So literally it’s just giving you their price and telling you to compare it to… This higher number. Why yes, I know numerical order! 
but people inherently trust that COMPARE TO means that it DID cost that much at some point.
We humans can be brilliant, but damned if we can’t easily be mesmerized by sparkly tricks.
10/$10s can vary from chain to chain. Some may demand you get all 10 of the same item to get the sale price. Others will have a group of items that are 10/$10 and you can mix and match the items to get to 10 for the sales price. My grocery store says they do the latter, but ALSO say you can just buy one and get the sale price. So they really could just use $1/item instead, but they know that 10/$10 really works. I do like that they’ll be totally upfront and honest that you don’t have to get 10, though. They’re not hiding anything, just taking advantage of the assumptions people make. And after reading that blog post, I’ve really learned to never assume any of the terms when I’m the one handing over the money!
You should be careful with saying “everywhere”, dude. I’m in Michigan and I don’t generally see this. More common is, as mentioned in my previos post, mix and match items to get to 10 or using it to entice customers but allowing the sales price to apply to any quantity.
The store I go to is a very local chain (5 ish locations in an area of metro Detroit), so they have more flexibility than large chains. They also are far more likely to have stupid awesome sales to move inventory NAO!!! like stroh’s ice cream 2/$3 when it normally is $5-6 each (everywhere, not just there). Or a one day sale on dannon yogurt that is suuuper cheap (gonna expire with a week) even if dannon is already on sale as part of the weekly advert (so they have it on sale, then that one day it’ll be on ULTRA sale). They have a space on their sign outside specifically to list today’s manager’s specials.
Again, FTR, completely not like this on this side of the pond.
Buy one get one free means precisely what it says. If you try to buy just one item often the cashier will point out to you that it is BOGOF, because you will pay the same price for one as for two.
I pretty much only shop at Meijer near the house, or E&L Meats in west Detroit (Mexican Town), and it’s always mix-and-match to get the 11th item, and you get the sale price for less than the x-for-y dollars price, but I don’t know what the other stores do. Since Farmer Jack closed, Meijer is still the only place without the stupid card (I have a famous Pit thread on that one).
Which local chain are you talking about? Randazzo’s? Just not convenient. Or Nino Salvaggio’s (only two stores last time I looked, but I love the place!).
The Safeway ads state very clearly when you have to buy a certain number of things (often mix and match) to get the discount. When their is a buy one get one free, the register tape has full price for one and a discount equal to the full price for the second. They also don’t have half price on the shelf tags, which they do for the 10 for $10 case, no minimum purchase.
Well, Kroger and Meijer do it in the metro-Detroit area. I just looked and I don’t see any kind of 10 for $10 in Meijer’s ad this week. Neither is Kroger, actually.
However, both do it quite often.