I am wanting to make the bottom tier of this cake. Does anyone have a suggestion on what kind of tip to use? I'm almost positive its buttercream and not fondant.

Giant Rose Tip #127D.

You can get a similar look with buttercream for sure, but that looks very much like fondant....and photoshopped for some odd reason?

 The rose tip has a bigger side and a smaller side. So, to all you professionals out there, which side should be up and which side which should be down when piping ruffles around sides of cake? I have forgotten. I am sure youngi would want to know this when they begin to pipe the ruffle. 

.........rose tip has a bigger side and a smaller side. So, to all you professionals out there, which side should be up ....

Almost always the lg/wider end is down and the narrow end up.  Of course there may be a few exceptions but as a general rule......^^^

Good catch 640cake!  Probably photoshopped to remove the watermark and place it on a different stand and claim it as their own.

I agree, those are fondant ruffles.

Now I get why you posted the other picture! @640cake. The more i stare at the picture you guys are right it looks more like fondant. 

Ive watched a few Youtube videos/ tutorials but can't find any similar to this.

Thanks for all your help, I'm going to try and do it with a rose tip but if that looks terrible all try fondant.