If you find a club, join it. If it requires AMA membership, join it, too. That's the usual path. Now, if you don't want to belong to a club, you can still join, but what would your reason be? What advantage would it give you? Don't say insurance, because that's secondary to any other you already have. Also, it's not required that you be politically involved in the AMA, so if you just want to support the Muncie site and museum, give'em fifty-eight bucks and have a cold one.

On a more serious note, look for changes in the future. What the AMA provides to its membership will likely change in the near future.