The sims I create in CAS are considered custom content, correct?
How come they don't save to the SavedSims folder? (I don't even have one;
inb4, YES I checked in My Documents\Electronic Arts\The Sims 3)

I don't know for sure because I've never tried it, but is there a 'share' button somewhere in CaS or when your finished sim is in the Library, the save bin in CaS; if there is, then this should be the function which generates a file for you.

They only go in there if you clicked the 3 dots on the Sim's icon in CAS (at the bottom of the screen) and selected "Save Sim to bin". If you don't do that, they don't go in the Sim bin, they only go into the Family bin. To get a Sim from the Family bin into the Sim bin, you need to go play them and do a Change Appearance to get into CAS, then you can click the 3 dots and "Save Sim to bin".

Huh? Whaaa? I'm lost.

Sorry a noob here, where is this CAS at? And the celebrity sims i downloaded do not show up in the sim bin in the game.

CAS can be found in "Edit Town". When you're playing the game, click the three dots in the bottom left and then click on "Edit Town". The sims you downloaded are in CAS. When you get there, click on the button which has a bunch of heads on it. That's where you'll find them.

You won't have a saved sim folder until you do what gnatgosplat said.

Thanks! I finally found them! lol.

So I have updated my sims3 game so it is now 1.14.... ect.
I didn't have a SavedSims folder, so I created one, like people have said...
I still can't find my sims, anwhere on the game (CAS, Edit Town/CAS)
plus I can't find the Save sim to bin thingy on CAS.

please help!!

You need to ask this over in the help forum (top of the screen: Help - The Sims 3) rather than bump a reaallly old thread in Discussion. Other people have had this problem so there are probably already some posts in the help forum that will be worth a read.