For cow call, a hoochie mama from Primos, or I maka da bull crazy or lip service or from buglin bulls, one of their cow calls.
Some would say get 2 different ones to have more than 1 sound.
Also, for beginners I would say get one of the primos bugles with the blue rubber ring on it.
Power bugle works to for beginners but those little thin bands get wrecked real easy.
If you really want to get into it, then most would recommend a mouth reed.
My go to brand is the Wayne Carlton Dome diaphragms, 1 in a cow call and I really like the 2.5 versions as I can do the most with those.
But they are hard to find (I have to order online usually).