It costs almost nothing to feed a cat that likes to live outside.
Make it feel at home at your place and it will rid you of numerous pesky critters. Cats are great animals, independent and loyal, when treated well.
If you just want to kill it, you know how. Why the thread then??
No kidding, cats will only warm up to you if they truly sense a connection, that are very picky My indoor outdoor born feral cat has a pet door. Comes and goes as he pleases requires very little maintainence has never made a mess or torn anything up. I can leave for extended periods. Just leave lots of dry food and water