As I mentioned at Transylvanian Dutch, the index to St. Louis County marriages is on microfilm and is available at three, if not more, different libraries in the area. I've never been to the County offices — I don't have much reason to go — but I'm sure they have a copy for public use, too. So the big deal is access to the index from home, or wherever you happen to be online, as well as ordering copies without having to go to Clayton.
My County research is rather limited because most of my St. Louis ancestors stayed within the City limits, but I have used the County marriage index on microfilm several times (though it's been a while). I'm certain the index covers the 1960s, but I think it probably goes even further: late '70s if not early '80s.
About the price ... if this system is what I hope it will be, $5.95 seems to me to be the perfect fee for online access.
Putting aside my personal needs, which are plenty in the City of St. Louis, the City should be doing this kind of project ASAP. I'm sure I've mentioned this before, but the original City marriage records (pre-1900) are in horrible shape and need to be digitized if for no other reason than preservation. There are a couple versions of microfilm available (one once described as a "bootleg" by a City staffer due to its inferior quality and apparently unauthorized filming), but they're not easy to use. The easiest version to read is the original books. But these are no longer available to the public. Yes, an archivist will do lookups, but I'd rather do it myself. What I've seen on microfilm is illegible (laughably bad) in some sections.
The City should partner with the StL Genealogical Society (for volunteers) and the Mo. State Archives to digitize the complete index and records (applications and licenses). Then the City could put these online and charge a fee. The City is always complaining about money ... here you go.
And while they're at it, someone needs to rescue the "unknown" or "lost" naturalization records from wherever those are hidden away. If the condition of the records is the main concern for not having these available to the public for years (decades?), one would think time passing by is not helping the situation.