It is important that you know I am a Georgia licensed estate planning attorney. Before you take any action on this issue, you should consult an attorney licensed in CO.
The legal fees involved in setting up a trust for you money will vary widely depending on what sort of assets are involved, what you are trying to accomplish by setting up the trust, and the level of experience/ability of the attorney you hire to do the work. In estate planning, as in most things, you get what you pay for.
If you have an organized and complete way to show your prospective attorney what your assets are (inherited and otherwise) PLUS if you know exactly what you are trying to accomplish in setting up the trust, you will make a more efficient use of the attorney's time. That will save you money if the attorney is billing hourly.
Some attorneys in this field do this sort of work on an hourly basis (i.e. - you pay the attorney his or her hourly rate for the time it takes to complete the work you want done). Other attorneys do the work on a flat fee basis (i.e. - the attorney will tell you the total cost of the work up front and you will pay that fee (or some part of it) up front to get the work started).
There are a great many kinds of trusts (e.g. - revocable living trusts, irrevocable trusts, IRA trusts, charitable giving trusts, personal residence trusts, etc.). That is why it is so important for you to be able to tell the lawyer what your goals are. If you can do that, a qualified estate planning attorney can help you to pick out the right trust (and/or other estate planning tools) to accomplish those goals.
The cost will depend on answers to a variety of questions and varies by attorney. What goals do you hope to achieve with the trust? Who are the beneficiaries? Do those beneficiaries have special needs? Are you involved in any litigation currently either regarding the funds or other matters? These are just a few of the relevant questions.
Contact an estate planning attorney and provide them more facts and they can advise you on the available options.
DISCLAIMER—This answer is for informational purposes only and discusses general legal principles, trends, and considerations and is not intended as specific legal advice regarding your question. This answer does not establish an attorney-client relationship.