Where can I buy tapioca flour easily and cheaplyvfor gluten free baking?

[medjool]

i usually use the doves farm flour blends and generally get decent results. I have perfected a basic recipe for each of pastry for tarts, scones, biscuits and cakes over a number of years, but given that there's a small possibility that one day we might emigrate somewhere where ready blended flours are not available, I want to have a bash at creating my own. There are a few recipes for flour blends online, such as Phil Vickery's which were published in the Telegraph, but having done a bit of research, it seems that some of the components of the blend are particularly difficult to get hold of or would significantly increase the cost of creating a kilo of gluten free flour blended for baking. Are there any gluten free bakers out there who have found and can recommend where to buy e.g. Tapioca flour at a good price ideally without having to make specialist online orders?

It's used a lot in east Asian and African cuisine, so maybe try chinese / African stores or market stalls.
But actually my big Tesco sell in in their Afro-Caribbean section.

It's also called Cassava flour.

Thanks for the tip Hazel!

Try eBay, I got some from there! It's lovely in a cake too, replace a quarter of regular flour and it makes it very moist.