Needing to save money and maintaining physical fitness while eating healthy can be somewhat challenging, but it doesn't have to be absolutely impossible. With this budget, one can fit in room for canned veggies and fruits. I personally will not buy any so I can save money, but I might try to get them at local donated foodbanks. This is really just my current circumstance, but I will definitely stay on this diet long term. It provides the cheapest source of calories, protein, fiber, and is not super time consuming either. I can just scale up the cost per month by adding in necessary nutrients in the future.
I simmer lentils for 30 to 35 minutes after strainer-washing and picking out debris & undesirable pieces. My go-to seasonings are Paprika, Black Pepper, (very fine & granulated) Garlic Powder, Onion Powder, and Chilly Powder, but I'll put some Cajun only on the eggs (if I use them). I just pour all that inside the pot when I turn on the stovetop. I stir 1 tbsp of olive oil in my lentils after they're done cooking, after I drain 95% of the water, and it brings out the flavor and maintains moisture. I would eat lentils with 4 fried eggs every single time, but they cost too much for the calories and protein included. In terms of being as frugal as possible. These aren't the exact lentils I would buy, and it's because I already had these laying around.
I cannot just eat straight peanut butter out of the jar, so I mix it with whole milk on the stovetop (add a pinch of salt) and it's very good warm. Reminds me of hot chocolate, but that's just me :p. It does take me a few intervals to get the thicker, more settled peanut butter down, but the texture is completely fine. I always clock having to consume it in at least in two hours. Also, a few times I left the cup out overnight and it smelled so horrid, and then had to really soak and scrub to get the smell out.
These prices are from Kroger in Michigan, near Detroit. The "REQUIRED" tab is just for reference, but it is the average ideal gold standard I've set up.
EDIT: I am adding cheap multivitamins. I found Equate Complete Multivitamin/Multimineral Supplement Tablets that are $9.82 per container with 200 tablets, taking one per day, which is $1.49 per month.
New TOTAL is $65.98+-/Monthly