I think you are asking an oxymoron type question “cheap claw foot cast iron bathtub”.
If it’s cast iron, it won’t be cheap. Buy it as locally as you can, that way it will be shipped in with other material. The further away you buy it, the more the shipping will cost you because this will be shipped by itself.
I recently saw a really neat block of tree which was hand carved into a lion that stood 3 feet high and was about 4-5 feet long (carved out of one solid piece). This was hand carved in Thailand or someplace over there (I forgot where). They wanted $1200 for this and $700 of it was shipping. You know the person who hand carved it only got paid a few bucks for their work (even though the work was excellent), the middle man will be getting most of what is left over after shipping. The weight of this piece was approximately 750 pounds. To my knowledge, they still have it.