Bearing costs oneself; the portion of expenses an individual must pay (e.g., when insurance or subsidies don't cover it).
この薬は保険適用外なので自己負担になります。
This medicine is not covered by insurance, so it will be at your own expense.
入院時の個室代は自己負担となる場合が多い。
The private room charge during hospitalization is often paid by the patient.
旅行中の治療費は自己負担になることがあるので海外旅行保険に入った。
Because medical treatment abroad can be at one's own expense, I bought travel insurance.