Besides Lucky Clover Trading Company, I’ve found these banneton selling at Amazon:
I haven’t used them so I can’t say whether they are good or not, but Lucky Clover has a 50.00 minimum last I heard so sometimes it’s better to just buy one or two. If you do a search on Amazon, you will come up with some good deals if you look for the lowest to highest prices in the search and not the relevant search. Many bannetons are still very high priced but some are really made with high quality materials.