I'm not quite sure what your question is, I'm going to assume (dangerous things assumptions) that you're referring to a proper grow light with reflector and separate ballast and one of those all in one floodlight things from homedepot?

If you're going to spend any money on a HPS growlight, get one designed for growing plants with and not one of those things designed for other purposes - they're worlds apart.

Also consider carefully the kind of reflector you buy with the grow light - not all reflectors are the same and some are a lot more efficient than others.

I'm not sure what size area you want to cover, but you might want to consider this before you decide on a 250, you may need larger. A 250HPS is a nice choice for small grows, partnered with a highly efficient reflector you maximise your light output and minimise your running costs.