retailmenot also claims a $20% code, so that will knock some money off. But I happily paid retail and I use it 100 times a day. It's also particularly helpful if you use an external monitor at your desk and regularly resize windows as you attach or detach the monitor.
Which would be WindowMaker.
Key benefits: virtually no development, Steve Jobs designed it, but for engineers on UNIX (well, NeXT), not idiots, and it's ~20 years old, so it's balazzzzzingly fucking fast on modern HW.
Stays the fuck out of my face, lets me get shit done.
I can't explain your downvotes...
The latter is probably the closest to a replacement to WindowMaker that I've found, but it has two serious deficits:
1: No "raise on circulate" (with window contents visible) when you're alt-tab circulating through windows. Makes it really hard to find what you're looking for.
2: No pinnable window list. In WindowMaker, any arbitrary menu (or sub-menu) may be pinned to the root window. F11 (or middle mouse on root) brings up a menu of all open windows (the windowlist), which can be navigated (arrow keys or mouse), and if pinned, stays persistent while you hunt down the particular window you're looking for. Very useful when needed.
To define shorcuts: Go to Settings, Keyboard, Shortcuts, Windows, and set your shortcuts.
To change the behaviour of middle-clicking or right-clicking on the title bar, install gnome-tweak-took, run gnome-tweak-tool, and go to the Windows section.
Works on my KDE4 (over Ubuntu) .. only been using KDE since about 98/99 and never knew about this.
This goes up there with double- and triple-click +drag for selection.
(I like Unity too, but it needs work on things like multiple monitor support)