Hello Geoff. Now, how do we define expensive... LOL.
In the Cotabato-Davao area, a Euanthe sanderiana in bloom would start at somewhere around 600 Philippine Pesos or about 14 US dollars, depending on the size of the plant and whether it has 1 or 2 spikes. It goes up to about 1,200 pesos or US $28.50 for bigger plants. Now if the flowers are beginning to wilt and the fair is about to end, they sell for around 400 pesos or US$ 9.50 on the average.