Here's the ticket. They work great for all focal lengths from 50mm to 135mm. Vignettes a little with wider lenses, despite the description. Inexpensive, and reasonably good quality. At that price, get a few. They have lens caps too. Again, reasonably good quality and inexpensive. Consider these items as consumables because inevitably they get lost or damaged no matter how good they are. Order $23 worth of stuff and shipping is free.

Forget the UV filters. That's just asking for more flare.