I discovered this forum when searching the web for a reasonably-priced brotform basket.
Finding none, I read some of the earlier brotform posts and realized that this baking item seems to be universally overpriced.
Decided to take matters into my own hands. It worked!
Grabbed a roll of 7/16" OD x 20' vinyl tubing at Home Depot, $5.55 with tax. I am confident this stuff is food-safe - I have used it for years for brewing beer and it's what moves air and water in millions of fishtanks around the world.