The cost of applying for a child visa to the UK varies depending on the type of visa:

1. Child Student Visa: £490 for the application fee. Additionally, there is an Immigration Health Surcharge (IHS), which is typically £470 per year of stay.
2. Child Visitor Visa: £100 for a standard 6-month visa. If applying for a longer-term visitor visa (2, 5, or 10 years), the fees are higher.
3. Dependent Child Visa: The fee depends on the type of visa the parent holds, but it generally ranges from £1,048 to £1,538.

These fees are subject to change, so it’s important to check the latest information on the UK government website before applying.