If you can't find it in Rona or other big box store, your best bet is a construction / industrial wholesaler... they usually sell it dirt cheap as well compared to the big box stores. IIRC, for a full length of 14" and 18" I.D. tube I paid just around $ 100 or so. Keep in mind they have a few different sizes that nest inside one another for shipping so if you want 24 exactly, bring your tape measure.
"You take the blue pill - the story ends, you wake up in your bed and believe whatever you want to believe. You take the red pill - you stay in Wonderland and I show you how deep the rabbit-hole goes."