Organizations like Carolina Biological Supply Company or Ward's Science often provide termites for educational purposes, though they typically sell workers and soldiers rather than a primary reproductive queen.
In the United States, the USDA APHIS strictly regulates the movement of termites across state lines because they are considered invasive pests. Shipping a queen often requires a P526 permit .
Ironically, most people "buy" a termite queen indirectly through Terminix or Orkin —not to keep her, but to ensure her removal. In the world of pest control, the queen is the "high-value target" because her death is the only way to collapse a colony. Why Buy a Queen?