Usage patterns
〈物〉が割高になるfor something to become overpriced (relative to value)
Smaller sizes often end up being less cost-effective.
〈物〉は割高だsomething is comparatively expensive for what it offers
This hotel is overpriced compared to others in its class.
割高な〈物〉を買うto buy something at an inflated price
Because I was in a hurry, I ended up buying an overpriced item.