George,
I purchased my flexible duct hose from McMaster Carr more than 10 years ago and it is still fairly reasonable in price at $4.04 per foot when bought in 25 foot (or longer) lengths. Here is a
link to the details, including its wall thickness at 0.015". When I bought this product, the price was much lower than today. By comparison, and actually a better deal, is 0.025" wall thickness clear PVC flexible duct from Wynn Environmental, the company that supplies filters and the short section of flex used by ClearVue's CV1800 cone to the dust barrel. You can purchase their 6" duct in 10' or 25' lengths for $46 or $92, respectively. Here is the
Link. Neither of these sources include shipping.
Hope this helps.