Trying to source a physical Spirit box enclosure

[DouglasHalse]

I managed to find an EMF-Reader on Amazon that I used for that device but I'm having trouble finding an enclosure that looks like a Spirit Box such as this one:

There are some available at Amazon but they are WAY too expensive (Roughly 90 USD) considering I only need the plastic enclosure. Do you know anywhere you can buy cheap plastic enclosures of different shapes and sizes?