@Mike Miller, if you are getting a California real estate salesperson license, you will have to hang that license with a broker. When you hang your license with the broker, you bring on certain liability as a salesperson, even if you're not representing any principals. So, you will almost inevitably have to pay certain fees, like insurance, licensing fees, and continuing education fees. As to MLS fees, generally, those fees are rolled in with the fees to join NAR, California Association of Realtors, and local real estate association (although some associations offer MLS only subscriptions). You will have to check your local association as to whether they have a non-MLS membership.
All of that said though, how do you plan to write your own offers on your own rental properties? In other words, what forms or documents will you use for your purchase agreement, disclosures, reports, statements, and all the other complicated documents that go into a California real estate transaction? Because you will not have access to the transaction forms usually used by California Realtors that come with membership in CAR, unless you join NAR, CAR, and the local real estate association. Then, at that point, why not just join the MLS for a few hundred dollars more and have access to comps and tax data?