I'm researching the currently most affordable temperature controlled soldering iron. Not necessarily purchasing just yet (what do I do with the power controlled iron?), but it might be interesting to discuss options, see if you guys have already found a good cheap unit, and just how low the price can go.
There are some "DIY" kits offered at various prices, using a T12 handle. Called "new Digital Soldering Iron Station Temperature Controller Kits"
Here is one variant ~$16
This variant seems to have everything except a 12-24 volt DC power source, and of course a case (unless the PSU is housed inside, I guess a cheap plastic case could suffice).
If you have a laptop power supply or other suitable supply already, the price is likely less than $20 total.
I also found an even cheaper kit with a miniature version controller at $11, without a display:
One advantage of this one is that it is really tiny. The obvious disadvantage is that it doesn't have a display, and quality of such a small board is questionable.
I doubt that there is a much cheaper solution available than those two (might be, please share). But what are your thoughts, and is there any other option to consider at a really low price point?