While the Court accepts you can pay a surrogate reasonable expenses, in England and Wales, you can’t pay or receive a commercial payment in pursuit of a surrogacy arrangement.
This can have serious criminal consequences. It is a condition of getting a Parental Order to become your child’s legal parent, that no commercial payments have been made, unless those payments are subsequently sanctioned by the court.
Commercial surrogacy is not prohibited in every country so it’s important to keep this in mind, especially when going abroad.
It’s not illegal to undertake a commercial surrogacy in a country where it is legal, and then return home to the UK, but the court will then need to sanction the payments if they relate to commercial costs. This will be straightforward if your costs are in keeping with local law and practice.