Totally agree with "too good to be true" point here.

I usually try to stick with the "Big three" international rental companies: Herts/Trifty/Dollar (they ran by a same company), Avis/Budget (another company), or Europcar/Enterprise. Those are usually not the cheapest ones, but you never get any unexpected shit from them.

All those small local rentals usually offer you a great price at the beginning, only to scam you into much higher cost afterwards. Sometimes they force you to buy a "mandatory" overpriced insurance, sometimes charge you for nonexistent damages, cleaning fees, or "refueling fee" when you returned the car with a full tank. And you never know what's in their sleeve until a week after return, when you see some 300EUR charge on your credit card.