Here is some interesting information. Apparently you can't order products directly from Flame King. I've sent them an email to get verification of that. I found that many web sites sell the Flame King tanks and refill kits. Many are out of stock at the moment. When I ordered mine in November of 2019, the tank cost was only $11.31, and the whole kit with one tank costs $37.34. Both had free shipping. Boy have prices gone up.
The lowest I had seen them was just prior to COVID when I first learned of their existence. I saw them at $12.99 each. Don't recall the cost of the refill kit. Since COVID prices shot WAY up.
The $44.95 for the refill kit, and the $14.99 for the refillable bottles at REI is the lowest price I have seen since COVID messed the world up.
Honestly I would LOVE to have been able to grab the refill kit and bottles at the prices you showed... Sweet!