That said..
>> taxes
This can never be free market, and some taxes (aka income taxes) is just unethical theft
> FBI, police
Should be funded in a variety of ways but absolutely could be privatized
https://reason.com/video/dont-abolish-the-police-privatize-t...
> Maybe we should get rid of army and hire mercenaries?
That is a little more tricky and would require an analysis of what we think the proper role of the military would be, but there are several proposals that replace the standing army (which is unconstitutional anyway) with something like the national guard controlled by individual states not the federal government
If everything is free market, why do we need government?
I know the answer, do you?
No taxes are not a service. Taxes are a compulsory contribution to state revenue enforced by the threat of violence. One can not simply choose not to consume a service and thus not pay the "taxes" for that service.
The fact is that the government, like a mugger, says to a person: Your money, or your life. And many, if not most, taxes are paid under the compulsion of that threat.
The government does not, indeed, waylay a person in a lonely place, spring upon them from the road side, and, holding a pistol to his head, proceed to rifle his pockets. But the robbery is none the less a robbery on that account; and it is far more dastardly and shameful.
>>If everything is free market, why do we need government?
we do not need the modern "nanny state" central planning style of government, we need a basic frame work of law that is far far far more limited that what most consider the modern government to be and is based on lawful defense of life, liberty and property nothing more.
A person is composed of Life, faculties, & production aka individuality, liberty, & property
Each of us has a natural right to defend their person, their liberty, and their property. These are the three basic requirements of life, and the preservation of any one of them is completely dependent upon the preservation of the other two.
The law is the organization of the natural right of lawful defense. It is the substitution of a common force for individual forces. And this common force is to do only what the individual forces have a natural and lawful right to do: to protect persons, liberties, and properties; to maintain the right of each, and to cause justice to reign over us all.
Since an individual cannot lawfully use force against the person, liberty, or property of another individual, then the common force for the same reason cannot lawfully be used to destroy the person, liberty, or property of individuals or groups.
Governments that are granted more power / authority than the collective organization of lawful defense are unethical in their foundation and purpose