Fume extractors can get expensive, but I really need to solder so it’s important that I have one. I had a 140mm fan lying around and a 12V power adapter, so the only remaining parts needed were filters and a case.
Cheap carbon filters are available on Amazon, but not of great quality (if you feel them, they’re not as stiff as the filters that come with the Hakko extractor, for example). It’s good to use two filters instead of one.
There are a couple cases available on Thingiverse, but most of them are for 120mm fans, and scaling up means the filters don’t fit nicely anymore.
Any 12V or even 9V barrel connector power adapter should do. 5.5mm barrel connectors cost less than a dollar each. The power and ground can be hooked up directly to the fan.