Getting a monitor on a DSLR* can be tricky. Base plates, cages, and magic arms all come to mind. If you want something a little more compact, cold-shoe ball mount is the go-to option.
Caleb Pike has a sweet little solution that uses GoPro parts that make a mount that only tilts and does not rotate or pivot. This makes it extra easy to tilt the screen with one hand and not worry about it rotating around. It stays perfectly aligned.
The idea is to get a cold-shoe to GoPro adapter, and attach that to the camera cold shoe. Now the top fo the camera acts just like any GoPro mountable tripod (or selfie stick). The original use of this device is to attach a gopro camera to the hot shoe and record while you shoot, but Caleb hacked this one.
The other half of this trick is to get a GoPro to 1/4-20 adapter (like this one or this one). The screw goes into the monitor and the GoPro mount thingy goes into the mount you just played on the cold shoe.
The entire setup costs around $20-$30 depending on the hardware you choose, which is not bad at all considering the awesomeness of the monitor mount.
*Yea I know I said DSLRs, but it goes for mirrorless cameras too