Well...the answer you get will probably depend on who you ask. Jim Butcher has mentioned that the first Harry Dresden book was written as an attempt to rebel against what his teachers were telling him. And, well...you know what happened. So there are authors out there who did get something out of classes. There are also authors out there who have degrees in English or Creative Writing.
Me, I think the money would be wasted unless you're the type that NEEDS another human to teach you. There are many resources on the web that will help you learn how to write, and of course you can study on your own. For example, I know Patricia Wrede has recently been blogging on writing topics. If you hit up a bunch of author blogs you'll find a lot of stuff from various viewpoints. Orson Scott Card also wrote a book on writing, although it was a long time ago and might be out of print. And, the discipline that you'd need to teach yourself is the same you would use to keep yourself on task and writing without an external force like a school or class or teacher hounding you. Also, I don't think you can get your 1,000,000 words of crap in purely through a class. A lot of learning is doing, experimenting.
Do you currently write at all? Or are you just considering picking it up based on your old high school days? I would say if you are not, right now, writing...start writing. You don't need a class to do it. Then once you've had some new experience, that isn't idea generation or "research" (procrastinating in the name of "research" is an easy trap to fall into--we all do it, particularly in the SF&F genre), re-evaluate if you still want to spend money on the class. Maybe you'll find you don't actually enjoy the writing part of it, and have no motivation to work at it. Or maybe you'll find you love it, you're learning a lot on your own, and you have some good questions to ask the teacher if you take a class.