You can of course buy books preprinted with word search puzzles. While some of these books are very good, the disadvantage is of course you can't choose what words should appear in the puzzle. Another idea is to use your computer _ with word search maker software, you can easily create your own puzzles _ that way you can choose words appropriate for the age level of your children (perhaps even choose the words they need to learn for school spelling), and tailor the puzzles too (for example by avoiding difficult diagonal words if creating puzzles for younger kids).
You can create word search yourself using nothing more than a pen and paper, but it can take you a long time! If you want to make some of these puzzles, the best answer is to use the computer _ with the right software, it's a piece of cake: type a list of words and a puzzle can be generated automatically for you in a few seconds. As well as varying your word list, using software will also allow you to experiment with placing words in different orientations. and create different size and shap puzzles.