One-time payments

Sometimes what a reader wants to pay for is one specific thing - a piece of premium content, say - not an ongoing relationship. A one-time payment is exactly that: a single charge, nothing recurring afterward, no subscription to remember to cancel.

Where it sits between a tip and a subscription

A tip supports you in general, with nothing specific attached. A subscription recurs. A one-time payment is the middle ground: tied to something specific, but done in one charge.

Getting paid

Same as everything else here - it lands in your Wallet.