I don't plan that much. Or at least not compared to what I called planning when I first started cooking for myself - trying to see what would be the cheapest immediate option for my meals the next week. Basically I watch grocery store ads and BudgetBytes.com posts. I try to keep a buffer so that what I am buying is not for this week but next week - fresh produce and meat is an exception. But for meat, I usually buy as cheap as I can find and freeze. I always check for manager specials, and only buy anything else if I'm low.

Over time I've saved the posts and recipes I've liked (I go for efficiency, cost, and variety over everything else) and make a week's worth at a time of whatever I have the ingredients on hand for. Over time, you just learn what ingredients you like to use and plan around them instead of specific recipes. Spices are important for this too. You can make all kinds of different dishes using the same meats/vegetables and varying the spices. I find this a much more enjoyable way to get the same results.