Registering a company is really easy and you can do it yourself or use any of the registered agent services that will charge you a small fee for it.
However the operating agreements, that would be signed by the members, are the most important piece of internal documents, especially for asset protection. The boiler plate ones that are provided by online services are very generic and are not optimized for the goal of your LLC. I you create an LLC for asset protection, you will need asset protection oriented operating agreement. If you want an LLC for a partnership in a real estate purchase, you will need an operating agreement optimized for that goal, etc...
That is why it is highly recommended to have a lawyer specialized in your field of operation to draft this operating agreement for you. Even if this document is not recorded nor published, that will be this document that will be your first line of defense or point of failure in court.
Now if you have multiple LLC having the same function, you can pay once for the first LLC and reuse the same operating agreement for the others.
In the same token, you can find some companies that are selling operating agreement templates that are focused on a specific goal. That may be cheaper than a full lawyer draft customized one.
You can also collect multiple sample operating agreements from other investors here at BP, and pick and choose the article that make sense to you and draft your own one. But that is risky if you don't know what you are doing as you may miss some big items. Also, you won't get any specific advice from non lawyers as it would be illegal to do so.
For me, I am more a DIY type and I have bought some specialized templates. I am also collecting operating agreements drafted by different lawyers from other members to attempt to compare them and try to understand the differences and see if I am missing something important in mine. For my core main asset protection holding LLC, I had my operating agreement reviewed by a lawyer.