Vapor Authority still has stock of the Baby Beast and Big Baby Beast kits.
I ordered a few from them a bit over a year ago and had no issues.
Edit: they have the TFV9 too.
You're not wrong, there are a few reasons. The I was first just trying to see if I can find a used tank to save some money (it's not just those tanks that are compatible, maybe I should update but the Vaporesso NRG, Cascade, skrr, geekvape cerberus, Illusion Mini, Shield, Aero and Aero Mesh Tanks, Eleaf Ello, and a bunch more are all compatible, so any of those would be fine.
Also, I live outside of the continental US. I don't think there are any difference in vaping laws, but many places, including Vapor Authority, don't seem to offer shipping here. I have ordered from people before, so I think they may just not want to deal with the shipping because it isn't the same amount as other States.
Here's some more of the compatible tanks:
- iJoy Exo S and Exo X Tanks
- Joyetech ProCore Aries Tank
- Squid Industries Peacemaker Tank
- Sigelei Slydr M and Kaos Subohm Tank
- Smok Baby Beast, Big Baby Beast, Baby Prince, Resa Tanks
- Teslacigs H8 Mini Tank
- Vapefly Fantasy Mini Tank
- Vaporesso NRG, NRG SE, NRG Mini and Cascade (with the adaptor) Tanks
- Vaportech Ark, Morpheus SF and Flip SF Tanks
- Vaptio Frogman Tank
- Wotofo Flow and Flow Pro Tank