Sounds like an interesting rumor/speculation to me. And that theory doesn't explain prices for TV sets and cars. Or..(in the USA, the price on the gas/petrol pumps? ALWAYS $2.49.9 I suspect it has simply become just a standard practice to hide actual costs.
If you have a product, whether made or from wholesale, that your analysis says that your needed profit shows it can be sold for $3.63, what do you think will appear on the retail shelf? Right..$3.99.
   "Sometimes", it the regular price is $3.49, a sale price will be $2.99... and similar prices. But even sale prices are carefully adjusted to move a product, and they often hide items whose "sell by date" is approaching. There are, of course, genuine "loss leader" items for holiday seasons, etc.

Be very sure the stores and manufacturers do not want YOU to know the actual production & wholesale price(s).