@William Knights You mentioned off-market home buyer - I assume you are asking about using a broker for resale of the property.
For the best market exposure, your listing should include an offer of compensation (aka co-op commission) that is competitive with what others are offering in your market, so buyer's agents have incentive to show it and sell it.
I'd start by Googling "flat fee MLS [your city, state]" and see what you come up with. Typically you'll pay the flat fee broker a small fee for the listing entry, but every broker is a little different in terms of what's included in the listing fee, so you should shop around.
Also beware of the sites who are offering super-low prices ($99 or whatever) - some of those are just lead services for the listing brokers, and you're just hiring whatever broker they send you to - who may or may not be local.