They don't mention what price they paid for it, but Tech Crunch estimated that THX was worth around $13 million back in 2002 and asked if that was what Razer paid for it, however, Razer's CEO, Min-Liang Tan, has said that "2002 is not today". This could be taken in one of two ways: that inflation has caused the price of THX to rise from what it was more than a decade ago, in which case the $13 million will have jumped up to $17 million or possibly something closer to $20 million, depending on the market valuation, or he's implying that the company's worth has shrunk since 2002 and that they did not pay more $13 million for THX from LucasArts.