Is a single-member LLC cheaper than a multi-member LLC?

Not at the state level — the fees are identical. The differences appear in federal tax treatment and in the accounting work each arrangement generates, not in what the Secretary of State charges.

Do I need an operating agreement for a single-member LLC?

Some states require one to exist even where nobody files it, and it costs nothing to write. Beyond the legal question, it is the document that evidences the LLC being run as a separate entity, which is the point of forming one.

Which state is cheapest for a single-member LLC?

The one you actually operate in, in nearly every case. Forming elsewhere means registering at home as a foreign LLC anyway, so the second state is added to your costs rather than substituted for them.

How Much Does a Single-Member LLC Cost?

A single-member LLC costs exactly what a multi-member one costs — states charge by entity, not by owner. The real question is what it costs every year after the filing fee, which is where states differ enormously and where most cost comparisons stop looking.

The state does not charge by owner

Filing fees, annual reports, and franchise taxes are charged per entity. A single-member LLC pays what any other LLC in that state pays; being the only owner changes your federal tax treatment, not the state's fee schedule.

By default a single-member LLC is disregarded for federal income tax, meaning its income is reported on the owner's return. That is a tax-filing distinction rather than a cost one, and it does not reduce a single state fee.

The recurring cost is the real number

Filing fees run from around fifty dollars to several hundred, once. Annual obligations run from nothing at all in a few states to many hundreds of dollars every year in others, forever.

Over five years the recurring side dominates completely, and it can reverse the ranking: a state that is cheapest to form in is frequently not the cheapest to stay in. Comparing filing fees alone answers the question you asked once and ignores the one you will pay repeatedly.

What genuinely costs nothing

An employer identification number is free from the IRS, and any service charging for one is charging for typing. An operating agreement is a document you write and keep; most states do not require it to be filed and none charge for it.

In most states you can act as your own registered agent at no cost if you have an address there. Commercial agents are a convenience worth buying for some people, but they are a market price rather than a state fee.

Common questions

Is a single-member LLC cheaper than a multi-member LLC?: Not at the state level — the fees are identical. The differences appear in federal tax treatment and in the accounting work each arrangement generates, not in what the Secretary of State charges.
Do I need an operating agreement for a single-member LLC?: Some states require one to exist even where nobody files it, and it costs nothing to write. Beyond the legal question, it is the document that evidences the LLC being run as a separate entity, which is the point of forming one.
Which state is cheapest for a single-member LLC?: The one you actually operate in, in nearly every case. Forming elsewhere means registering at home as a foreign LLC anyway, so the second state is added to your costs rather than substituted for them.

Run it for your numbers:

Price it in your state