Worked in pricing for a big retailer, it 100% works and retailers don't even like doing it, but it's basically a necessity to get baseline sales. It's WAY easier to have simple even number prices that calculate easily and get percent off sales and clearance prices that make sense. Really the only items you see it on are items competing with other retailers, so kraft mayo that every store has vs. A store brand soda you don't care about volume on. The Mayo you better have $5.99 instead of $6.00 or it looks like you're ripping them off. And even if they sell it got $4.99 it still keeps people thinking it's a complex price difference rather than an even number they can compare more easily.