How can we prevent that EEG chip manufacturers do stock market speculations with products which we are interested in?

Since several years we are interested in EEG devices. As soon as we showed interest in those, many product where offered to us, mainly containing the ADS1299 EEG chip from Texas Instruments. At the same time we observed that sellers to stock market speculations with those products. OpenBCI modules on Aliexpress have randomly scattered prices …