I want to make something similar to the brewtroller. I want an Arduino, the post that got me going was the mash monitor post. I need a soldering iron to make the temp probe and i will need to solder other things as well.
I just don't want to buy a POS and I also don't want to buy something that is way out of my league.
For what you need just do as missing link suggested go to radio shack or some other hobbiest store and pick you up an ok iron... either something in the 40-45 range or a multi ranged one say like he has thatsd 20-40 watts..... you DONT need anything fancy....... something with a few different tips may be nice it gives you ALOT of flexibility on what you can solder ....
That being said I LOVE my pace digital sensa temp iron then again I got it for free lol
Once you get your iron, practice soldering wire to different things and learn how to tin wire. Always make sure you touch the solder to the wire, not to iron tip. When you have the wire hot enough, it will actually suck the solder up and leave a shiny finish. It takes very little solder to make a good joint.
Stop, if you are soldering on a PCB board like the Arduino , you don't want a solder iron over 20 watts, ideally look for a variable one. I build loads of electronics and have 5 different ones, you will damage IC components quickly, and always use a heatsink . Weller is a great one, but there are others.
You can't go wrong with Weller. Like what has been pointed out, if you want to do PC board work and wiring, you need more than one or an adjustable soldering iron. For only $20, this one from Fry's is ok: FRYS.com | Velleman
It's adjustable and it's a station style. I've been using it for a while now. If you use it a lot, the barrel will begin to loosen because of the way it is attached. I just pull it apart and bend the metal retainer back and it's good for a couple more months of use. That's pretty much crap to have to do that, but remember it's only $20, has replaceable tips and maintains a consistent temp.
The Weller Jcdillin pointed out is a much better choice if you want to spend the money.