2 for $25:
Lenovo Smart White Bulb (B22) 
Lenovo Smart White Bulb (E27) 
2 for $40:
Lenovo Smart Colour Bulb (B22) 
Lenovo Smart Colour Bulb (E27) 
2 for $50:
Lenovo C35 E14 Smart Filament Bulb
Lenovo A60 B22 Smart Filament Bulb
Lenovo A60 E27 Smart Filament Bulb
Lenovo ST64 B22 Smart Filament Bulb
Lenovo ST64 E27 Smart Filament Bulb
2 for $60:
Lenovo G95 E27 Smart Filament Bulb
Lenovo G95 B22 Smart Filament Bulb
God I hate having downlights. they are so expensive to get smart versions for.
Depending on what 'smarts' you want to add, existing systems etc - look at replacing the switch (eg the Arlec GridConnect) or get something like a Shelly to go behind it.
This is the best advice. Smart bulbs are still dumb, because they won't work if you've switched them off at the wall. I personaly have Zwave switches behind all my light points (Shelly is a good option too - but I wanted my lights independent of the home wi-fi). This way my parents (late 60s) can still use my lights, and they can still be controlled via voice using Google Home/Alexa/Siri.
If looking for Gu10 downlights similar to Hue, I recommend checking out Gledopto that can be bought from AliExpress (about 50% what a similar Philips/Lifx bulb costs). These pair with a Philips Hue bridge and coupled with my smart switches I can get great scenes, routines etc all throughout the house.
How do you get voice control without having the lights on the home wi-fi?
@v8o: I run an open source home automation platform called Home Assistant, that you can integrate with Google/Alexa/Homekit. So while I can control the lights via the cloud, they are also independent of it. I ran it for 18 months on a Raspberry Pi3 with a Zwave dongle - so quite cheap to get started. Key with home automation is to ensure you can run things locally and not rely on cloud services (in case the internet goes down, or the manufacturer no longer supports the service.)
Thanks OP. Was waiting to buy some as I'm trying to get wifey to get used to using "smart home" products before we build (though in most cases we'll go with smart switches rather than bulbs)
Note it's $0.10 cheaper ($24.90) from Hardly Normal but that's 20 minutes walk while JB is right next door to work :)
Thanks OP - out of interest, for the B22's (and not knowing much about lighting other than what's online) are the Lenovo's considered far superior to the likes of the Kogan equivalents which you can get 4 of for $30?
Thanks OP. Also available at The Good Guys for the same price if that's more convenient for anyone (discount applied in cart)