To help your parents out, just let them read my reply here.
First, you must absolutely ignore the concept of % off MSRP (edit as a means to gauge a good deal). That is not a good way to go into a car purchase. I agree that it could be a part of the purchase decision since emotionally people love to boast about how they got a killer deal. But I cannot stress enough that % off MSRP is not going to be the key decider.
So what is the decider? The industry has a term called vehicle net pricing. This is what a buyer actually pays for any given vehicle on any given day; BEFORE any stuff like tax, title, registration, etc. Since every state is different (and I can’t tell if you’re in CA or NV), I’m just going to focus on net pricing.
If you’re financing/cash-paying a vehicle, your goal is to find a net price that gets you as much car as you desire for the least amount of money paid. Some cars have an astronomically high MSRP, and they give you very little car in return (see a Dodge Hornet). Some cars have a fairly low MSRP but give you a lot of car (see a Honda Pilot Touring). You could get 20% off MSRP on that Hornet, but that could be a bad deal compared to if there’s a Pilot for 8% off MSRP that is a better fit.
Leases just add complexity into the equation, but ultimately the logic is the same. You’re not looking for the biggest discounts. You’re looking for paying the least amount of $ for the most amount of car that suits your needs.
Being said, to help your parents, first understand what they want out of their next car. Then, lay out vehicles that meet those criteria and wants.
Establish a range of net pricing you feel would represent a good price and start hunting. In each circumstance, you must be willing to walk away from a bad deal even if you like the car. With enough time/sweat you’ll be able to get a car for a good price for them. Sure, some LH die-hard may be able do better on that one car, but we’re talking about a general purchase. Not some unicorn hunt.
Orrrrr just contact one of the brokers on this forum and have them ship a killer deal to your parents in NV. Save yourself and your parents the pain of the haggle.