It might be similar to a Motte and Bailey Fallacy. Though that one is more focused on distinct but related definitions than it is for distinct but related situations. Not the exact one that you are looking for, but the related concepts might be a path towards an answer.
Of course, “always cheaper” in this case means less money up front, but much, much expensive more down the road than the initial cost.
Of course, the down the road cost isn’t usually that visibly connected to the “make it illegal” plan, so conservative governments love it.