back in my day (2014!) it used to be 100tbt to 1mil bells! though looking through my post history im seeing 100tbt to 2.5 mil - its probably closer to the latter now maybe?
edit:
apparently 800k for 100tbt back then??
it fluctuates, i think the average was about 1.5mil, it may be more/less nowadays!
edit 2:
just seen 200k for 1tbt? i have no idea anymore.. but i'll certainly be following this thread to find out!!