I’ve been planning to buy a low whistle, but I’m wondering about which one to get for a beginner. I’ve heard about Mid east cane whistles but I’m somewhat skeptical about these. If anyone could suggest a good low whistle for $30 or $40 I would really appreciate it. Please help and Thanks. 
Guido Gonzato makes nice PVC whistles. He is a member of C&F and has a website. He is in your price range.
ecohawk
Using Guido’s free plans you could also make your own. It’s not hard and the thrill of making music on an instrument you made yourself is hard to beat.
Methinks I shall look into this… 