Fly use to not require a credit card and could use the free tier. I setup a few instances just to trial about a year ago, about 6 months ago these instances started costing about $12 per month, I just logged in the other day to discover this. I feel now if I wanted to use their services they would back bill me for these test accounts I wasn’t using. Feel they could have notified me when they started charging so I could have shutdown the accounts.