What a host actually provides

Accreditation you can book against, supplier relationships and preferred rates you could not get alone, errors and omissions insurance, back office and commission tracking, and somebody to ask when a booking goes wrong. On day one that is most of a business.

What it costs

A share of every commission, sometimes with a monthly fee. Splits vary widely and the headline number is not the whole story: a lower split with better supplier rates can pay more than a higher split with worse ones.

The questions worth asking before you sign

How is commission tracked and when is it paid. Which suppliers are preferred and at what rate. What happens to your client list if you leave. Whether there is a minimum. What support actually exists when a client is stranded.

When independent starts to make sense

When your volume is high enough that the split costs more than the services are worth, and when you have the supplier relationships and the operational discipline to replace what the host was doing. That is a later problem, not a first-year one.