To turn out to be expensive; to cost more than expected.
車の修理は結局高くついた。
The car repair turned out to be expensive after all.
安い材料で作ると品質が落ちて、長い目で見ると高くつくことがある。
Using cheap materials can lower quality and, in the long run, end up costing more.
あの店は見た目は安そうだが、結局高くつくよ。
That shop looks cheap, but it ends up costing you more.