Sometimes Thrift (second-hand) Stores have them, at least here in the US (I'm not sure if second-hand stores as big a thing where you live as they are here). Trying out a used cheap second hand one might give you a better idea of what features you want when it's time to invest more money.
If it's a stick blender you want, the most important-to-me feature is that the blending arm be removable for easy cleaning. A close second to that is that the blending arm be long for when I want to blend larger amount of oils. No one wants to use a SB and have the motor part get into the soap, which can happen if the blending arm isn't long enough.