Inelastic just means consumers aren't sensitive to price. The classical example is prescription drugs. Consumers are not price sensitive b/c they NEED those drugs. As such the seller can raise price and not see a drop off in sales.
I think a good example of a highly elastic good is hamburgers. Is McDonalds raises burger prices by 300% there a ton of other options for consumers to switch to and sales will drop.
A better example is brand name prescription drugs. State substitution laws end up meaning that when generics come on market, a lot of consumers become proce sensitive by law since the pharmacy must fill the prescription with the lower priced generic. However, anyone who is still buying the brand name at that point is highly inelastic - they really want the brand name only for whatever reason. Thats why the brand name version of a drug usually spikes up in price when a generic enters the market - theres no way to compete with the generic folks on price so at least get as much out of your smaller remaining market segment that you can by using their price inelasticity
In particular it's not only brand name medications, but patented ones, because then there is by law only one supplier, and the temporarily high price is on purpose as a reward for developing the new drug.
The problem we have then is that it's getting paid for by insurance, and we don't have a good mechanism to distinguish between essential things and merely new things. If somebody comes up with the cure for cancer, letting them soak the insurance companies for 20 years is a fair trade. If somebody comes up with a pill that does the same thing as the combination of two pills that had been standard practice previously, but can convince doctors to prescribe the new thing, letting them soak the insurance companies for 20 years is some kind of regulatory failure.
Well actually, the only patent prescription drug is a bit elastic since insurance/PBMs negotiate on price. In referring to the particular case of a formerly on patent brand name drug that goes off patent that spikes in price.
You'll notice that even over the counter non patented brand name drugs are more expensive than the generics - brand loyalty breeds inelasticity
I think a good example of a highly elastic good is hamburgers. Is McDonalds raises burger prices by 300% there a ton of other options for consumers to switch to and sales will drop.