Hello Zijstock,the cheapest way would be to use acrylic sheet available from DIY stores,for the frame work you could use the pre-shaped slotted ramin stripwood mitred at the corners,make five sides neatly assembled at the corners with the acrylic sheet lightly glued into place,glue three sides together,then the top,for a base use MDF,the final panel could either be hinged or screwed into place,for a cabinet with shelves glue a ledge made from stripwood or if you can get it clear plastic square rod,then slide in the shelf.
There are probably other ways but this gets around the problem and expense,plus the weight factor of plate glass.
When cutting the acrylic sheet leave the protective membrane in place until you have completed the cutting otherwise there is a real danger of scratches.
The above will make you an economy no fuss cabinet for your oil rig.