My sewing class tutor gave me a great tip to make bias binding without buying a gadget; just using a pin and an ironing board!
I hope you can see in the photo that I have pinned a longish pin to the ironing board and folded over the bias band under it. As you pull it along you can iron it.
The gap determines the size of your folded bias binding, so with a bit of adjustment you can make different sizes.
Soon I'll show you what I did with it!