You can spend a few dollars to repair and additional functionality, but the total cost of expenses is much lower compared to the expenses when buying a new car.
If the seller will not show you the written guarantee, which is the biggest red flag you can see.
They then use a strategy known as a "negative return policy", while providing very irresistible lure of a "free sample".
Buyers can usually negotiate in a third of the margin of the warranty of the car.
If your afford the acquisition of this specific element is fixed, you can then choose the variation repaired.
The best way to get a good deal is to shop around. Auto dealers put pressure on purchasing a car extended warranties on the day the car is sold.