An interesting point there!
I have storage boxes for all my models to keep them dust free. It’s quite expensive to make even these. But in the living room I have my Fruit Ship Granada as pride of place.
Rather than make a conventional display case which would indeed be expensive, I constructed one which enables the boat to be easily removed but still clearly displayed.The photos illustrate this.
Basically I made a base, background and sides frame from veneered chipboard which is mounted on the floor as shown in the photos.
The front is 6mm plate glass supported on the base and held in place by slotted supports. The plate glass top then rests above this by gravity.
The boat can be removed by simply lifting off the top and the inside of the case cleaned by lifting out the front panel.
It all works very well indeed and I think makes an attractive solution.
Colin

