The key owner's balance and every endpoint's cost

The allowance of the key's owner for the current month, what their keys spent and what remains, when it resets, their purchased credits left, and what every keyed endpoint costs in API credits. ownerType says whose balance it is: the user's own on a personal key, the organisation's on an organisation key. The allowance pays first, then purchased credits, no more of them in a month than spendLimit less purchasedSpent; a call is refused with 402 when its cost exceeds remaining and what purchased credits may still pay together. This call costs nothing and is served whatever the balance. Costs 0 API credits (call class free).