How many tables do you have? I found some at this site : Glass Dome Display | Triple Thick Glaze | Bronzing Kit | Wood Platform Base - Casting Keepsakes
for about 19 dollars a piece. And this site: Glass Domes, Domes, Acrylic Domes, Dome Displays
had some nice ones in the $10-15 range.

Good luck! Let me know if you need more help.