Some items seem to be more "safe" than others. I recently decided to buy a power inverter so I can use my laptop in the car without running down the computer's battery. Because there were so many inverters, and so few bidders, I ended up buying 3 or them, one for each vehicle. I paid $1.26 + 12.99 shipping & handling, $2.99 + 9.99 s&h, and $6.50 + 8.00 s&h. That's an average of $13.91 each including all costs. Discounted prices were from $28 to $35 each from other sources. In 2 cases I was the only bidder; I beat one other bid for the $1.26 model.
But, you're right, of course. At the time, I was in a jam to fix a race car, and couldn't find the part anywhere. I was actually willing to pay the $1000 if I had to. But, as I said above, it was risky.