another vote for muscle food and much cheaper than any local butcher
Indeed. Though my local butcher is quite competitive, but the quality is hugely better than MF. But... saving money is always good, and if you can have a slightly cheaper but pretty good quality food then why wouldn't you (unless you can afford it of course!).
That said, I love MF, I'm a regular customer and will continue to be, and the quality is miles better than supermarket stuff (bar some of the premium shops), and the bulk buying aspect is great, as well as the range of foods they do. Though personally I'd just stick to the main meats, their meals, veg, and other bits aren't particularly good from the samples I've tried, and not that good value.
As for bulk prep, you can roast/cook a week's worth of food and put it in the freezer (even rice/potatoes/veg) and actually a short blast in the microwave is great. I personally keep some sweet chilli sauce at work to give it a bit of zing. Prep time is 20 mins or so. Roast/cook breasts/other meat, cook veg and or rice/potatoes - all done in parallel. Split into Tupperware wait to cool whilst you do other things, and into the freezer. I only keep in freezer because just in case I go out for lunch or my schedule changes. Cooked rice in the freezer is okay - in fact if you cook rice and then shove in cold water straight away to cool it, and then freeze it, it'll safely store in the freezer. Though you should only reheat it once as usual.
Snacks, well nuts, fruit, if you're that way inclined you can make your own flapjacks (good protein flapjacks are not that hard to make, and don't have to contain insane levels of butter or sugar). IF you're not shy of spending money, you can buy protein snacks from protein suppliers, I don't particularly like them, but a lot of people rate them. Beef jerky is great, if expensive. Tuna is cheap and an easy snack, as are things like hummus. You can make lots of cool dishes and snacks with quinoa too - again some prep time, but is quite fire and forget, even pop corn (if not salted to hell and back, or laden with toffee or butter) is pretty decent. In fact you can buy a bag of kernels which will last you over a week for about £1. I quite like roasting chickpeas, with a bit of seasoning they're an amazing snack. If dairy isn't an issue, cottage cheese or quark is lovely - add some roasted nuts to it and you've got a really satisfying snack. Nut butters as long as they don't add salt/sugar and/or palm oil, they're fantastic too, but hugely moreish.