The only problem with going to substitutes is though they may contain the same or many of the same ingredients as the solvent you are trying to replace economically. Is the ratio of each and the other ingredients. I have experimented with other chemical blends only to find that days even weeks later there was an adverse reaction/effect.
Still the best solvent IMO is Weld-On#3 which is available in large cans. A can will last a long time especially if you transfer small amounts into a working bottle. With all of my building my can has lasted years.
I'm all for saving money...Like good alcohol the purer the better. 