How long’s a piece of string really. I would say that generally online hasn’t caught up in the truck parts world and counters are still generally cheaper. Nine times out of ten you can go to the same place as them and buy direct but that assumes you’ve got the time to do that and can wait.
Those air fittings will probably be cheaper again from Tubegear and likely where they’re buying them from. Also always pretend to be trade if going direct and your normal trade supplier has let you down.