The best inst. bags I've ever come across are by Crescendo. Each one is custom made to order so you can pick your exact fabric and colors. Also, they have a bunch of different bags for many instruments & combos.
I hate it when I get black under my lip from playing flute. I finally found the fix - lip guards! I get mine from Flutacious where they have both a transparent (pictured above) and a variety of designs!