Art Frames Cheap

How to build a mobile wall partition?
I need to build a wall on wheels for an art gallery, they need to be about 8 feet high, and it needs to be build for cheap.
My idea is to install 4 heavy duty casters on double layered 3/4 plywood at 1′ wide and 4′ long. Then on top of that build a skeleton frame out of 1x4s and attach 1/4 ply to the frame.
Does anyone have a better/ cheaper idea on how to do this?
If you’re an artist, you should have plenty of ideas..
Pre-Cut Economy Mat Frames/ Picture Backs/ Easel Backs For Cheap