Tallbald you will most likely get many different answers to your question. I personally have several thousand tied up in a machine and tools, and I have a very long wish list as well....all this with the intention of supplementing my income when I retire. I would say that whatever the cost to keep you occupied, active, and happy is well worth it....and if/when you can make it pay that's icing on the cake. The cowboy should be a big help to you. I think that if I were in your position I would just buy the material, hardware, etc to make a couple of each item you are thinking of and see what sells the best. That would give you a better idea of the direction you should take. Just my 2 cents worth and wishing you the best of luck.