TCP is the cheapest at about $18-20 per bulb; but you will need a starter kit because the TCP bulbs connect through their own hub and integrate cloud-to-cloud with ST. So if you just need 1 or 2 bulbs, the cost per bulb is at or above the Osram. If you’re going 3+, then the TCP will be cheaper. I would search around to check on how the integration with TCP is working though and consider the extra hassle of an additional hub.
The Osram Lightify is a really good bulb. Connects direct to ST. I modified the official Cree ST device-type to add the color temperature selection and provide some feedback on what that temp is close to. It ranges from soft white (2700K) all the way past the TCP daylight to 6500K, which is pretty blue.