If you look at my Copyright Information page, you will see that I allow anybody to print, copy and distribute my puzzles free of charge. However, there is only ever one puzzle per post so your printing costs might make this uneconomical.
If this applies to you, take a look at the Free Printable Sudoku page on the Live Sudoku site. This lets you download PDFs which contain easy, medium, hard or evil puzzles, with either 4 or 6 puzzles on each page. You are then free to print and copy them as often as you wish. The page has other options too, including the ability to create blank sudoku grids.
I downloaded one of their books of evil puzzles, which contained 60 sudokus. I checked the grade of the first grid on SudokuWiki.org. This gave it a rating of Tough / 177. The solve path used naked pairs, naked triples, pointing pairs and a Y-wing. You can see the puzzle below if you would like to try it yourself: