PVC pipe works just fine. So does plexiglass. Save your money and take your lady to a movie and dinner.
A well attended to XYL or GF will view your radio fun with a lot less of a hairy eyeball if you make the time.
Or you can get her interested in radio...
It would really help new amateurs who want to build antennas to find an older copy of the ARRL Antenna book. There are too few explanations and too little data in the current editions. By old I mean say pre-1989. Cruise hamfest tables and Ebay, there are plenty available pretty cheap.