As I said in an earlier post, the goal behind OAMC and Freezer Meals is to have a dinner ready to go in a flash. For those with freezer space issues, the whole OAMC thing is impossible.
That said, so long as you have at least a standard sized freezer, you can still have go-to meals waiting for the just in case moments.
I suggest keeping a couple of frozen sauces and pre-cooked meats in the freezer, but separated. This makes for a fast meal when you need it.
Most of the sauces that you might consider are Italian based, but not all. If you're counting carbs, then I don't know what to tell you except to think creatively for pasta alternatives. However sauces are so easy to heat quickly and you're saving money by not buying the stuff in a jar.
You can find base recipes all over the internet for standard sauces such as tomato, piccata, stroganoff and (gasp at the carbs) alfredo. All of these freeze well. Alfredo and stroganoff can be tricky, depending on the recipes, because of the cream.
Cream based sauces can easily be frozen without loosing flavor, but the attractiveness may not remain intact. The cream separates from the water and gives it a strange look. However if you taste it, you'll not notice a difference at all. Looks can be deceiving!
I freeze my sauces in 2-cup plastic freezer containers overnight. Then I dip it in hot (not boiling) water and pop out the freezer block. I wrap each block in foil, then toss them in a gallon size zip bag, label and toss in the freezer.
For space issues, you could pour your sauce into a large freezer bag, then spread it flat and lay it in your freezer. Once frozen, you can stack them up like you would files in your filing cabinet. The larger the bag, the flatter it will be. Yes, that's common sense but worth noting.
The downfall to that method though is thawing out. If you don't allow it to thaw on its own, it's virtually impossible to remove the bag, with the contents still frozen, and keeping the bag intact for reuse. Simply put, you have to rip the bag off. Not a great thing. However if you're lucky enough to remember to take it out in advance then this won't be a problem for you. I'm the kind that remembers to take it out when I need it.
Now keeping cooked meat in the freezer is another good idea. After much calculation, as well as frustration, I realized that buying a 5 lb. bag of Great Value brand frozen chicken breasts was the best deal for me. As with everything else, it comes with its own problem. Like buying a bag of potatoes, the breasts do not conform to any one size. The bag comes with a few really big, turkey sized, breasts and some tiny cornish hen sized breasts.
Just as in potatoes, you just use a little common sense. Two small breasts is about the same as one large and so forth. In the end, I'm usually left with only one or two oddly sized breasts. Sure, I could still use them - after all I will be buying another bag - but I use them instead as an opportunity. I saute them, then slice them in strips or cut them into chunks.
I place the cooked chicken in sandwich bags, then place those in a larger bag and freeze. Then when I need to do dinner in a hurry, I just pull out the amount of cooked chicken I need. This works for any meat to include browned ground beef, roasted beef (or pork) and so forth. The idea here is to package it in smaller sizes so you don't have too much when less is needed.
Now I have meals that I can use when I simply do not want to cook dinner. This helps prevent the itch to pick up fast food or buy boxed meals.