It might or might not save money to move the kitchen to another space in the house, whether it is larger or smaller.
Here are the major cost factors to consider:
> plumbing (supply and waste removal pipes)
> structural issues
> hot water supply
> heat and air conditioning
> gas line
> leveling the floors (a garage, for example, might be two or three feet lower than the floor level of the rest of the house).
You probably need to compare the specific costs of adding vs. moving your kitchen, especially if natural gas lines are involved.