Here are my tips!
It depends on how you meal plan. If you go through your cookbooks looking for recipes as your starting point, yeah, it could definitely get expensive! Instead, I do stock up on sales as I see them (I spent about a month constructing a price book for our basic pantry supplies at various stores around, so now I know what's a good price and where to get what for the cheapest). I keep a running list of what I have in the house and START THERE. We always have tons of dried beans and grains, so those tend to be the backbone of many meals. We usually buy tofu and/or tempeh and have that a few times a week. We almost always have onions, carrots and mushrooms, and our sides generally consist of potatoes, greens, broccoli and salad. So you start with what you have and use that list to construct your meal plan - looking for recipes that utilize those main ingredients. This way, you're using what you have and just supplementing the few little things that you need for specific recipes (things I don't keep around because they go bad, like fresh herbs, other types of specific produce, etc).
I find it also just helps to write down what meals you make even after you've eaten them and keep that in a list somewhere. Then when I'm feeling uninspired I'll read over past lists and go, Hey, we haven't had THAT in a while!
Another trick that may or may not work for you is to make index cards with your favorite dishes on them (1 dish per card). I made them so that I have staple ingredients listed on the left, and fresh/need-to-buy ingredients listed on the right, and then the cookbook/website address for the recipe on the back of the card. If you're a visual person or someone who doesn't like to commit to a certain meal on a certain day, having these tacked to a bulletin board is nice, because you can easily rearrange them for the week as you need to. I also make a note at the top of each of any time constraints to be aware of (soaking beans, letting things rise, etc) So it's still all there, so you know that if you're having beans tomorrow you need to soak them the night before, etc.
Another thing I do occasionally is pick a legume and a grain for the week. Make big batches of each to have in the fridge and plan meals around those. For example, we have like 25 lbs of black beans in our pantry. I'll cook up 1-2 lbs and make black bean soup (freeze some extra!), black bean hummus, sweet potato and black bean burritoes, and then the other nights vary it up with tofu dishes. Same with chickpeas. Big batches of brown rice are also great for rice and beans, adding to soups/stews, and we also eat it heated up like oatmeal for breakfast. Cheap staples that you can make tons of ways!
Can you tell I'm not married to one particular method?
They're all good for different things - you just really have to start and see what works best for you.
In terms of past meal plans, here are all the posts on my (woefully ignored of late) blog that list
meal plans.
