Depends on the application. With a commercial truck with the typical 13L to 15L engine, the application is a full gallon of the stuff at an oil change. Haven't seen what Wally World is charging, but the truckstops are pricing a gallon at $90-$100. Of those that I have checked with that used it, I have not seen that it has any considerable benefit. I have no desire to put that stuff in my $20,000 engine.