The best for your dollar when it comes to a whistle in plastic. Better for beginners than pretty much any standard whistle and also chosen by pros, so save your money on metal bodied whistles with plastic heads and try these.
Both the Oriole and Kildare series below with the pitches I have in stock. Each comes in a case with fingering chart and a container of cork grease for the joint, as each is two piece and tunable. A little bit of overlap for some of the pitches due to bore size difference in each series… Oriole has the tightest bore, and it goes from there.