This may help someone. No affiliation, just re-posting. R450 seems like a good price
https://www.gumtree.co.za/a-motorcycles-scooters/morningside/2010-yamaha-xt-transponder-keys/10010288336261012442363409
https://www.gumtree.co.za/a-motorcycles-scooters/morningside/2010-yamaha-xt-transponder-keys/10010288336261012442363409