Warning, this will be a long post
I read tons of books on budgeting and none of them really clicked with me until I read this one book called 'I Can Teach you to be Rich' written by this popular financial blogger. He said all those books that say never buy a latte or never do this or that are nonsense, it's all about percentages. He gives percentages for what you should spend on: fixed expenses, savings, investments and guilt-free. Just plug your income amount in and it will tell you what to spend on each category.
For example, let's say you earn $2000 a month in take-home pay. Your percentages may look like this:
65% for fixed expenses ($1300)
10% for savings/emergencies ($200)
10% for retirement/investing ($200)
15% for guilt-free fun ($300)
You can tweak it a little if need be. For example I personally have minimal fixed expenses right now since I am lacking a car, a house, a dog or a baby (but YMMV on those) so I do not spend 65% on fixed expenses and have bumped the savings and investing categories up a little. I also have some variable income every month that I have not tossed into the budget because it ranges from $100-500 depending on how many extra hours I put in (I tutor and babysit on the side). So I lump that into 'guilt-free' and use it for longer-term goals like saving for a vacation.
Let's look at that fixed expenses category now. Personally, my preference is to budget for essential groceries in this category and use the guilt-free money for going out with friends. So, how much do I have for that? What you do is you start with your total amount ($1300 in this example) and see what's left after you have deducted. So, to use my own situation as an example, this is (roughly) my fixed expense budget per month:
Rent ($915 including renter's insurance)
Bus pass ($121)
Cell Phone ($35)
Bank Fees ($10 and I get unlimited transactions for that)
So, that leaves me with about $300 for food, drug store and other miscellaneous necessities. Most months, I don't spend nearly that; I typically spend about $50 a week on food, but I live in an expensive city and my neighbourhood stores are on the pricier side unless I travel (where I would eat up any savings in needing to have a car). When I lived way downtown in a more slummy neighbourhood, there were some cheaper options
Personally, I feel it is better to budget more and then not use it all. I love the system from this book because it doesn't matter how much money you make, it will still work. If you make more money, you'll just have more to spend in each category. If you make less money, your contributions for things like retirement savings will be comparatively less but will be the same proportion of your income relative to someone earning more.
As far as grocery planning goes, I am extremely lazy cook, so what I typically do is this:
I shop twice a week. On every shopping trip, I replenish whatever staples I always keep on hand (soy milk, brown rice, frozen fruit for smoothies, rice noodles, peanut butter, trail mix ingredients, canned beans and tomatoes etc.) and buy ingredients for ONE proper recipe which I choose before my shopping trip. Then:
1) I will cook that recipe and eat it for two meals. Usually, I will freeze part (or the components of it) for a make-my-own frozen dinner (for example, the other day I made a recipe that served two and involved half a can of pea soup used as a stir-fry sauce; I did not freeze a ready-made because it involved noodles, but I froze the rest of the soup and if I want to make the meal again I just need to thaw the soup and add tofu, broccoli and cooked noodles and I could have the meal again in about five minutes)
2) For the other meals, I will either eat something from my freezer stash (for example, I have that stir-fry ready to go by using the reserved soup in the freezer) or I will make something that is readily on hand with pantry ingredients, like noodle soup or a salad or something. Sometimes, I will buy a convenience item but this is rare because I have food allergies and feel really awful if I accidentally eat something I shouldn't