I researched a lot of different ideas for this when we added chromebooks to our classroom. In the end I sent the principal an email with some different options and he let me have the expensive one! It is basically a filing drawer with moulded slots for devices and fits ipads and chromebooks. I love it. Everything is away and tidy. I got the big version and I think it would blow your budget unfortunately.
Before he agreed to the expensive option though, I had plans to make something like this, https://100things2do.ca/magazine-rac...rging-station/
I had seen it in action and I hate looking at messy cords.
I have also used dish racks before I got too many devices - They worked brilliantly for the ipads, but were too small for our chromebooks. We cable tied multi boards to them, and it makes them easily transported around the school.
I hope you find something soon.