Reddit mentions of uxcell Computer PC Fan 12V 4 Pin to 5V USB 2.0 Adaptor Connector Cable Cord Wire

USB to 4 pin molex is super common and easy to find. Just then buy an adapter from molex to fan power

https://www.amazon.com/gp/aw/d/B00VG6UV2O/ref=mp_s_a_1_1?ie=UTF8&qid=1475254389&sr=8-1&pi=SY200_QL40&keywords=usb+to+molex&dpPl=1&dpID=41Y6G9u4zhL&ref=plSrch

https://www.amazon.com/gp/aw/d/B00DU8ZZ0O/ref=mp_s_a_1_1?ie=UTF8&qid=1475254425&sr=8-1&pi=SX200_QL40&keywords=molex+to+fan+adapter&dpPl=1&dpID=41XRRy3aZsL&ref=plSrch

There may be a cable that skips the middle man, but I have confidence that these are popular and probably work well

Here is the desktop version of your link

somthing like this?

Regarding the external cooling solutions, I mean something like these:

https://www.reddit.com/r/Surface/comments/51d1o2/surface_pro_4_external_cooling_rough_prototype/

http://www.surfaceforums.net/threads/my-attempt-at-external-fan-cooling.14516/

https://www.youtube.com/watch?v=jR9SWFJAp5o

Perhaps someone who's into 3D-printed stuff can make available a reference layout, that fits standard 60mm or 80mm case fans, so people around the world can make their own easily with an adapter cable like this (https://smile.amazon.com/Computer-Fan-Adaptor-Connector-Cable/dp/B00VG6UV2O/)?

Cheers.

Something like this should do the trick if you don't have a regular PC power supply with Molex connectors (the 4 pin thing) inside the case, but have USB. Without actually seeing what you're dealing with, it's tough.
https://www.amazon.com/uxcell-Computer-Adaptor-Connector-Cable/dp/B00VG6UV2O

Fellow keezer owners! Lend me your ear!

I bought this computer fan to run inside my keezer. I think it uses a molex connector? What is the cheapest/safest way to power this thing with a wall outlet? Can I splice it into a USB somehow? Old cell charger?

Alternatively, can I use something like this to run it to like, an Apple charging block?