If they don't actually have any $5k trucks but claim they do in order to lure people in to try to sell them $25k trucks that would be a bait and switch that would run afoul of the law in several states. The FTC would probably also have something to say.
I tried to buy/lease a car recently and not a single one of the advertised prices was actually available. For example the commercials that say “lease a new 2021 Subaru for $250/month”. You get to the dealership and any of these following reasons could be why the car actually costs way more:
that price is for a base model, they only have supreme models available at the dealer
that price is only available to people with a 800 credit score
you need to put 5,000 down and only drive the car 10,000 miles per year
that promotion ended
*the promotion is still going but that dealership doesn’t participate
Etc, etc etc.
The list goes on and on, but one thing is for sure- you will never get a car at the advertised price.