What is the purpose of free enterprise? to allow businesses free rein to influence economic policies to give consumers freedom of choice to keep government out of business

To give consumers freedom of choice.

It is true that a free enterprise system gives much freedom also to business, but to say it "allows businesses free rein" goes too far.  Even in a free enterprise system, there may be regulations and safeguards that will protect against abusive business practices.  And while a free enterprise system is not directly controlled by government, it is a more fundamental purpose of free enterprise to give consumers the freedom to make their own economic choices.