I refuse to stop mentioning my wife 
You know, oscillating fans, the little 12"-20" fans that rotate on a pedastil with three speeds, usually? As a relatively poor kid, the air conditioner in the bedroom is the first one I’ve ever owned in my life. I grew up around these rattly white plastic fan things. Three-blade, cheapo plastic, bought-from-walmart $20 specials. Usually Intertek branded in North America, because lol. 
For most of my life these goofy things have just been ambiently existing objects in my house, I’d dust em when needed. Recently though, one of the older ones, (mfd Oct 2013) a real generic 16" job with a garbo aluminium stand, started running really slow.
At first I assumed it just had electrical issues, y’know bad caps or a short or resistance, whatever. When I took it apart today though I noticed there was a ton of hair wrapped around the center shaft that turns the blade. (We both have extremely long hair) Cut it all away with a utility knife, but at that point, with the fan’s cage open and the blades off I got curious… 
Unscrew the back of the cage from the front of the fan body, (where the motor is housed) look inside, turns out the entire thing is clogged with dust and hair, mostly cat hair. Got a duster can and blew it all out, the thing expelled a cloud of fuckin’ dust on my balcony 
but when I got it back together, while it now ran fullspeed (wow!) it made a pretty painfully loud squeaking/scraping noise while spinning.
I wasn’t real sure what to do, but my wife suggested oil… not motor oil, we don’t have any since I’m not a gearhead, but like, canola oil or sunflower oil? Just applied with the hard end of a cotton bud along where the shaft connects to the motor, and it’ll trickle in??? I assumed canola oil would be conductive and this sounded like a really bad idea to me, I was sure it’d explode. I even put the fan outside, closed the balcony door and ran a cable inside to test, in case it magic-smoked itself.
Sure enough though, dumping food oil down the motor of a standing fan results in perfect silence…? 
Reassembled the thing, buttoned it up and it was literally good as new. Oscillates smoothly, spins stronger than when I first got it, and is dead silent. We did it to our other two goofy canadian tire special fans the same way, and it’s been great for them too, somehow. Fucking canola oil…
I make this post mostly because I have never even heard the concept of repairing/servicing these standing fans entertained. It’s like toasters, or how non-techbrained people view computers: just a simple appliance. I knew about dusting them of course, but otherwise for my entire life whenever one crapped out, BANG instantly trashed! Another $20 down, unlimited disposable replacement upon standing fans! Turns out that curiosity and basic disassembly ability (all we used was a phillips head screwdriver, a duster can, the aforementioned oil, windex and paper towels) will probably let you keep these dumb things running for a lot longer than ten years. Whoda thunk it??? This does make sense, given that many oscillating fans are on 24/7 in the summer. Something like that easily earns a bit of maintenance, and this is gonna be a yearly check-up activity for us now!
So I guess the point is, if you’re not rich enough to air condition every room where you live, or even just have standing fans anyway, give em some love and they might benefit a lot ✨
the problem with using organic oils is that they’ll go rancid and start to stink. other posters had good suggestions for cheap alternatives. My first instinct would have been to grab wd-40 but they say don’t, and I don’t know enough to argue the matter.
WD-40 is actually a very poor lubricant and can gum stuff up. I use sewing machine oil for my appliances since it’s relatively cheap and I figure if its good for my typewriter then it must be good for just about everything else.
Sewing machine oil/light machine oil is the exact thing to use here. Light machine oil is good for just about everything except lock tumblers.
The “WD” stands for “Water Displacing”. It’s function is to force moisture out of small gaps in parts, usually in preparation for some other operation. It has some lubricant in it but the lubricant evaporates very quickly.
If you want to remove rust get a penetrating oil or penetrating catalyst. In the US that’s PB Blaster. The chemical will force it’s way in to rust and do some chemical fuckery that breaks the rust up and makes it easy to remove.
For oiling light machinery, anything household, I use a product called 3 in 1 oil that you can find at most hardware stores. Works on locks, hinges, small motors, anything that’s not too intense.
Yeah rancidity might be a problem, (just read about it in a comedy practicalmachinist thread) even though I used a really miniscule amount. I’m in the room with these pretty much all day every day so if they start stinking I’ll douse em in rubbing alcohol or dish soap and use the 3-in-1 I just ordered. Usually I would cludge stuff like this, but I’ve had enough situations now where proper lubricant would do.
I believe WD-40 has wax or something wax-like in it, which can make it good for weather resistance in cases like outdoor tools or maybe a bike chain, but it just hinders things otherwise