Aura db automatically turns off in every few days or so

Hi sorry if it is already answered. I searched here but couldn't found.
I am doing a side project and I had created a free instance. it is used rarely. Everytime now and then it seems the instance is stopped. Is this intentional ?
How can I make sure the db is up and running all the time. Do I have to pay for it ?

@info.metalogic

If you want a Aura instance to remain running even if idle for some time then you need to move to Aura ProfessionalEnterprise and at cost