More Than a Penny’s Worth: Left-Digit Bias and Firm Pricing, presented by Avner Shlain site.stanford.edu/sites/default/… 
Using scanner data, Avner estimates the size of the left digit bias to be about 20 cents for small grocery items. That is, they act as if a $4.99 carton of milk actually costs $4.79.
Given this size of this bias, grocery stores should price *everything* ending in 99 cents, but they don't. What must the stores *think* the bias is to explain their behavior.
The paper estimates that firms act as if the consumer left-digit bias is only 2 cents. This underestimation of the bias costs the stores about 2% of profits. If they were totally unaware of the bias, they would lose 3-5% of profits.
This was one of my favorite presentations, since it went so carefully layer-by-layer through the bias, its effects on the demand side, and the supply side meta-bias.
For more on left-digit bias, see this paper by @NicoLacetera, @Devin_G_Pope, and @JustinSydnor: faculty.chicagobooth.edu/devin.pope/res…
