In other words, you're using "overcharging" to mean "the price went up". That doesn't seem like a very good use of language; there are lots of valid reasons why the price might have gone up.

As for retailers using the word "sale" to mean "we raised the price a week ago and now we're dropping it back to where it was before, in the hope that you'll think it's a great deal", that could certainly be described as "shadiness", yes, but since you appear to agree with the market being free, the free market should sort that out just fine. If such practices hurt consumers, on net, then consumers can respond by not buying from such retailers.