Got a cheapo Viltrox JY-670 Ring Flash from eBay the other day. For $105AUD, I'm pretty happy with it's quality: dual, independent flash tubes, ratio control, good build quality. I find it's 1/4 full brightness is enough at iso200 for most shots I take, so it's plenty bright enough. It also has two LEDs as a focus light, for shots taken in the dark.
Doesn't have TTL functionality though, which means you need a subject that will stick around to get a good shot, or lots of experience in flash use. The cable between the (locking) control unit is quite stiff, so when taking photos in portrait, you can't position the ring flash to have it's tubes