The other day I was shocked to find a bag of oat flour on the inner webs advertised at $23.00 for a 22 oz. bag. I couldn’t believe it. I would never pay that!! It is so easy to make. All you need is a blender and some old-fashioned oats. Only use old-fashioned oats for flour, no quick or instant. Add it to the blender a cup or 2 at a time and use a spoon to push the unground oats down to the bottom.
You can use a sifter for finer flour and a lighter dough, or leave it course for a good, grainy bread flour.
If you only want a little bit, for example for a roux, you can use a little electric coffee/herb grinder to make as much flour as you need.