Making a dollar bill pile and the basic planes keep clipping through each other as if they do not register the other cloth meshes.
I’ve tried expanding their face so they’re not just one sided, scaling them up and generally messing with the the collision parameters.
Excuse the simple problem, but I have yet to find the solution elsewhere.
I’m pretty sure blender can’t do that style of animation. Even a single piece of cloth colliding with the ground plane does not work. The collision system is unstable over time. You may want to consider other software for such a shot, or abandon the concept of cloth and just use RBD.
Why are you saying this ??? 
flipflap.mp40001-0250.mkv (35.3 KB)
Edit:( okay this one seems no to be embedded)
Make a ground (out of cube) add collision modifier. Make a plane above the ground a little slanted, add a cloth modifier. Repeat for second plane. Animtee whats wrong?? First one also need a collision modifier.
Paper_cloth_test.blend (1.3 MB)
Currently using 2.82 and result is the same and adding a collision modifier to the planes causes severe glitching.
Which version are you using Okidoki and would you post a .blend with your example?
In the meantime I’ve used Rigid Body with a variation of bent bills and it got the job done, but I’m interested in improving the scene if possible.
For something like this if you really need it to be 100% physics you could use Houdini.
For anything, but 100% real you could rig a bill with some bones and do some quick hand animation. With something like ghost ik it could go really fast.
One set of bones along the long side is where most of the bending of the bill will be. The other side is too short to get much bending most of the time. Maybe combine that with rigid body physics.
Made mine with 2.93.1; tested yours with 2.82.12 and added a collision modifier on first/green Plane ! 
and it works.
Following the tutorial and using Soft Body in a single mesh worked just like I wanted, thank you!
