If you're moderately handy, you can make your own for next to nothing. An old computer fan, a power pack, some rare earth magnets, and some epoxy and you're good to go. I'm sure there are some good tutorials in the DIY forum here or on YouTube.
I just recently put good effort into aerating (after about 3 years of not really doing much - never had an issue though). I do find that my krausen is much higher and my yeast much more active, and quicker at that, when I put good effort into aerating. Its all beer right?
My aeration method is to stir vigoriusly in the better bottle with the sanitized ass end of my plastic brewing spoon. I crank it around one direction 10 x or so anf then reverse direction. That seemed to be "working" but I have been wondering about the DIY attachments people make for drills to whip it into a nice creamy concoction....
And now you see that Evil will always triumph, because Good is dumb!