Filtering isn't even really for advanced amateurs, since the cost of a filter pales in comparison to the cost of the scope. 20-30$ will get you something that will get rid of most of the low-pressure sodium (orange) emissions. Novices, like me, have a small set of filters they use to improve various views of different objects, and a lot of these filters will be completely defeated by white lights. I'm pretty busy, and prefer to do my observing from my backyard, rather than wasting a couple of hours in a car, so actions like this (replacing easily filtered lights with broad-spectrum ones) is a little irritating.