A 30 round pmag is not an essential item and the prices people are paying this week are nationwide and not localized. The persons buying them are speculating that the prices they paid will not be short-term if a ban is put in place. Some are speculating that the prices will actually increase.
What is happening is "free market" not "price gouging". Unlike a Socialist Market where prices are set by government regulation, A free market is where the price of an item or service is determined by supply and demand with little to no government control. The oposite of a socialist market. This be it beany babies, furbys, pink power rangers, or Pmags. They are not essential items, but all had demands that exceded the supply. Our free market simply adjusted with more production and price increases after the market clearing.
The example of the gas station price gouging does not apply to free market as it was short-term and localized related to a natural disaster.
When it involves essentials such as food, fuel, shelter, medicine and equipment needed to preserve life, limb and property it is not only considered price gouging, it is illegal.
A mother may have thought the pink power ranger their daughter was demanding for christmas was an essential item a few years ago, but it was no more an essential item than a 30 round pmag is right now.