Honestly, for under $50, you can’t really get anything high-quality that’s not a bullet, IMO. There are lots of battery-powered hard plastic toys in that price range, and they’re all pretty similar.
My favorite cheapo vibe is the Turbo Glider because it’s waterproof, cute-looking, and has a lot more power than most vibes in that price area. But if you really want something good, you’re going to have to save up at least $90 for something from Lelo, Jimmyjane, Jopen, or Leaf.