It's not just HF. I've ordered small parts for some of my name brand tools, and had to pay more for shipping than the cost of the parts.
As far as parts costing more than a new tool, that's an unfortunate turn that our society has taken. We now live in a disposable society. Fewer people do their own repairs, even if you can find a repair service near you, the labor can cost more than a new item. I remember when there was a repair shop for just about anything within a short distance, no matter where you lived. Now, just try to find a repairman for a TV, vacuum cleaner, radio, or sewing machine. They're all gone. You can't even find someone to rebuild electric motors anymore.