Just want to see how much others are in…for those who keep track that is, lol.
No competition for lowest/highest amount, just interested.
Im in $3,868.53 so far. But I’ve bought a lot of “extra” stuff to try. Could probably be right at $3000 if i add up just what Im actually using right now.
Hard to say. I built a new house with KNX bus system and dimmable 24V lights almost everywhere. I think the extra charge, compared to “standard” electrics, was about 8.000-10.000 € ($10.000-12.000). But I did everything myself, so I only had the material cost.
Plus afterwards some ZigBee lights (for floor lamps etc.) and sensors, some wifi sensors… But I think this additional stuff is not exceeding 500 €.
I buy A LOT of cheap sensors, LED strips and various boards from Aliexpress. So I’m not in for very much. The most I spend is the $5 a month on Nabu Casa.
To give an example, a few months ago I made the electrical heater in my daughters room “smart” and integrated it as a thermostat in HA. Not including the price of the heater the price breakdown was as follows:
Wemos D1 MINI - £2.19
Relay module - £2.14
DHT22 module - £2.84
The actual price is a bit less as I have added the full shipping onto the price for each one. In reality I usually order quite a few of each unit and use them elsewhere.
So for £7.17 I have a smart heater and can see the temp and humidity in my daughters room.
About everything is now “smart” in our house, including the light in the barn back in our garden. I work in ICT for decades now, but i have an electronics background (worked for years at Philips and Panasonic as service engineer before i made the switch to ICT), so i built some of the stuff myself. I bought light bulbs, sensors and hubs, but everything else i made myself. Smart ledstrips included. ESP’s are real cheap, but very versatile. Really love’em. 
I tried Ikea Tradfri, had a hub and some white bulbs and stuff, but Tradfri caused nothing but problems and lost it’s key for the connection at every reboot of the HA server, so i ditched Ikea and replaced all Ikea stuff with Tuya RGB bulbs. Much better.
I built the server from spare parts i had, so no cost there.
i now have:
2 xiaomi hubs 40,-
2 xiaomi zigbee bulbs 20,-
9 xiaomi zigbee motion sensors 90,-
6 xiaomi zigbee switches 60,-
8 wifi rgb bulbs 42,-
1 ESP8266 outdoor temperature sensor 4,-
2 ESP8266 5mtr ledstrips, 1 white 1 RGB 10,-
1 ESP8266 wifi power meter reader 5,-
1 ESP8255 doorbell 4,-
3 ONVIF security cameras 60,-
1 smart wifi dimmer 20,-
Hassio Server running Linux Debian10 0,-
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total 355,-
I’m in a lot of $$$ but I’m also in a lot of kicks in having HA available and implementing things - especially in these unusual times. A good investment
Mostly small purchases, but it adds up. Lockdown has seen my house get quite a bit smarter lol.
I’d guess maybe £4k overall spread over 3 years. I have like 50 sensors, 20 sockets, mower, 3 wall switches, vacuum, alarm, front door lock, 10 echos. About a grand on Hue bulbs 
Luckily I used to have an aquarium hobby otherwise spending £50 for one light bulb might seem crazy.
Im always on the hunt for new projects around my smart room controlled by HA. Im living in a shared apartment with cappy wifi and we cant lay normal cable internet, so im using my phone as AP. One AP with openWRT is connecting to my mobile and from there the signal is handled by my firewall that my dad gave me. But i dont like having AP always on, so i got one another AP that is connected to the crappy wifi (which i cant do anything about, thats my conditions i have to deal with). When i dont need it for like gaming, so crappy wifi AP gets switched off.
So my whole cost so far:
Server: Nothing, its an old office pc from 2006 my dad gave me
RGB in my PC (controlled by HA, since cheaper): around 8 Euro, didnt need to buy the fans the controller lights up
Around 5m WS2812b strips, still got something of the roll: around 25 euros
My node for controlling my IR amp, my rgb mousepad and my Xbox: around 15 euros. Including the destruction of a few ESP´s. oops.
Both Wifi AP´s: around 40 euros
MY node for screen backlights, air sensor and controlling the atx psu all my appliences on the pc desk getting powered with: around 20 Euros.
12V to 5V car charger adaptor: around 5 to 7 euros. Used to have a normal smartphone charger at my desk powered by the atx psu
Ikea tradfri 5 Button remote: around 15 Euros
Ikea tradfri wall plug: like 10 euros.
Universal Remote for controlling my xbox: 10 to 15 euros. If i include the failed remotes (beeing to cheap quality to drop from 50 cm without cracking is hard, isnt it?) its like 25 euros in total.
Pre-flashed zigbee to usb dongle: around 16 euros from amazon.
So, all in all its like 200 euros. Im trying to build most stuff by myself or salvage parts from broken PC´s, laptops, tablets, smartphones or any other damaged electronics. What isnt broken, gets repurposed.
Next projects are the DIY smart speaker, making some rgb light panels and adding some smart stuff to my workbench
