I noticed that John MacArthur's "Strange Fire: The Danger of Offending the Holy Spirit with Counterfeit Worship" is currently on sale in Vyrso for $2.99
https://vyrso.com/product/31955/strange-fire-the-danger-of-offending-the-holy-spirit-with-counterfeit-worship
Also, pre-orders for Michael Brown's response, entitled "Authentic Fire", are due to ship tomorrow. The pre-pub price for this book is $11.99
https://vyrso.com/product/52045/authentic-fire-a-response-to-john-macarthurs-strange-fire