No. If they ask say it's none of their damn business, but I've never had someone ask. As to where, other than online you might be able to find them in a garden shop. Some places have hydroponic shops, they almost always have them.
On line ...inside sun .e-bayect.. home improvment stores usually carry a 70-150 watt hps or mh from$70-$150 w/ ballast n all they usually carry from 70-400 mh or hps BULBS...street lights are typically a 250 hps with a ballast that is capable of handling 400w......a guy i know aquired one... GOOD LUCK ....GOOD GROWING