Solicitors fees will vary according to the firm, the size of the estate, and according to the service being sought, such as if you were looking to have a will written up, or have a solicitor act as an executor of the will.
There are different fees and charges associated with the public trustee, depending on the role that they play.
However, if the Public Trustee becomes your executor it will also charge you for the things it has to do to run your estate. As at 2021 its charges for estate administration on a simple estate are 2.2% of your assets. There is also a rising scale of costs for transferring assets to a beneficiary. It charges commission on the receipt of all income into the estate, and other various fees for other activity, e.g. account keeping, bank transfers and so forth. You can look at the fees and charges here.
You can also contact the Public Trustee on 1800 068 784 to discuss fees and charges.