Tang Shixun wanted to acquire some Thunder Cultivation Techniques, and Guo Xiaosong directly stated that there was no problem—after all, your Taiqing Sect is wealthy.
However, after Tang Shixun looked at the Thunder Cultivation Techniques, he expressed that... there are too many of these techniques, and I can't afford them.
There are over ten thousand Thunder cultivators in the original Thunder Plain—actually over fifty thousand, among which various techniques... there are at least a hundred with a notable reputation.
Guo Xiaosong also knew that Tang Shixun couldn't possibly buy all the techniques—if you dare to buy them all, even millions of Spirit Stones wouldn't be enough.
It's not that all the Thunder Cultivation Techniques are worth that many Spirit Stones, but... if someone buys in bulk, who wouldn't raise the price?
