Buy plexiglass...you must be kidding, I just drive over to the nearest glass store and ask if they have any plexiglass scrap that I can have. They want to know what I'm going to use it for... antenna insulators I say, I'm a ham radio operator and love playing with wire antennas and the plexiglass makes nice insulators. Usually they walk in back and come out with an arm load of scrap, I thank them and carry out my goodies. Some get pitched in the trash once I get home because they're too small to be of use the rest gets set aside for "playing".
Try it, the worst they can say is "Get outta here kid", and think geeze don't these hams ever grow up.