If you are after some cheap 'ok' wireless bulbs take a look at MiLight / LimitlessLED (they have various brand names). You can pick up bulbs for under $15 and the bridge for about the same from AliExpress.
They have the same issue as these in that white and RGB are seperate modes (so you can't control the saturation), but other than that they work fine and don't have any cloud "features".
The protocol of the bridge / app has been reverse engineered, and there are various libraries on GitHub:
Beware: the bridge for Milight bulbs also communicates outbound to a mystery server for Internet control of the bulbs. The actual RF protocol has been documented and implemented as Arduino code, though, which is what I use for my installation.
I have one of these and this is why I blocked the wifi bridge from any outgoing network access. The mystery server then just uses the MAC address of the bridge as the "authentication" of where you get to control the lights via the app.
Having a separate wifi network (and separate VLAN for wired) IoT devices sounds like a good idea, and is something that I'll be doing this weekend...
(Also will port-scan the MiLight bridge to see if it's got any other interesting services on it)
Last time I looked into the MiLight devices, it seemed like the protocol didn't support RGB but instead converted it into a more constrained space - is that accurate?
This is correct, if you want to use these for mood lighting you probably also want RGB+saturation as the effect will be much nice. For a cheap bulb that can be controlled programatically these are great though.
They have the same issue as these in that white and RGB are seperate modes (so you can't control the saturation), but other than that they work fine and don't have any cloud "features".
The protocol of the bridge / app has been reverse engineered, and there are various libraries on GitHub:
https://github.com/mwittig/node-milight-promise