Rectangle Pro

Rectangle Pro is the same app with the parts that need a business model behind them. The feature people actually buy it for is saved layouts: arrange four windows the way you like them, save that arrangement, and bring it back with a hotkey — or have it restore itself the moment a particular external display connects. If you dock and undock a MacBook every day, that alone justifies the price.

The rest is refinement over the free version: throwing a window to another screen with a flick of the mouse, per-app rules so a given app always opens at the size you want, and a deeper settings panel with more snap targets.

The $9.99 is a single payment handled by Paddle, valid on three Macs at once, after ten days free. Outside the US the same 9.99 number appears in your own currency with VAT already inside it, which is unusually tidy.

Who should not buy it: if your window management consists of "left half, right half, maximise", free Rectangle does that identically and Pro will feel like nothing changed. The other thing to know before paying is that the developer has never said what happens at a major version bump — most likely nothing, but no promise has been made either way, so treat this as a licence for the app as it stands today.