I have won crossword competitions on several occasions in local newspapers, journals, etc usually small money prizes of �10ish but I have never won one of the big national ones. I used to regular win the Dingbats competition in the yorkshirei post, the prize always being a Waddingtons Board game so we have a cupboard full of boardgames now.
I won �50 once in the take a break, years ago now though, but I keep trying. Everyone has the same chance of winning. providing all your answers are right of course.
The You magazine competition twice, first prize �100 and the runner up �25. Sir Lancelot, Parker Pen. Local paper, Oxford Dictionary worth �20. I have been trying The Mail on Sunday Prize crossword for eight years so if I ever win I probably wouldn't get the postage it's cost me back. But the thrill of opening that letter to say you have won even a small prize is wonderful, as you have said you will never make a fortune but it's fun trying anyway.