Hello @antoninovara 
Thank you for your interest about TB3!
As you said that the sale of TB3 Waffle has ended last year.
However, today we introduce new TB3 called Waffle Pi 
The big difference between Waffle and Waffle Pi is that the main SBC(Single Board Computer) and Camera are substituted with Raspberry Pi and Raspberry Pi Camera.
(More detailed about it, please following Link)
TB3 series provide simple bringup. So secondary school students easily setup and operate it by following TB3 Wiki.
TB3 supports simple examples including interactive markers, obstacle detection, and patrol and advanced examples SLAM, Navigation.
We also already update Waffle Pi in Rviz and Gazebo simulator. You can operate it how it works even on your map (Ref : http://gazebosim.org/tutorials?tut=build_world&cat=build_world)
If you have any information about TB3, please visit our Wiki or www.turtlebot.com
Or Have any question about development with TB3, take a ticket in github issue page.
Best regards
Darby