Board Game Arena

When is the Education technology meant to activate?

I read it as though it was mean to activate at the end of every round and didn't require a worker to use (ie. a free culture action every turn.)
However in the game I played it didn't activate every round, so was wonder what the condition I didn't understand was?

You still have to pay $4, did you have enough money?

Maybe not, that's probably why then. I probably took free to mean didn't need to pay for it and didn't need a worker from the symbol underneath.