I'll add my 2-cents worth here, as I have on other threads about this topic (AND what I tell family members who ask--even my sister who is now on Atkins with a grocery budget of about $150/month for 2).
If you stay away from the specialty products, you can actually save money on this WOE. As suggested, when it's feasible, buy meat in bulk and re-package it yourself. Take a little time to shop around at local stores and familiarize yourself with their niches. WalMart, for example, carries quite a few products which, while low-carb, are also a reasonable buy. Fred Meyer has a health food within their store which carries many 'health food store' products for less (we buy a box of cereal that my daughter really likes about once a month of so). We also have a huge grocery store in our area that has a really large bulk section. I buy nuts, vital wheat gluten and soy flour there cheaper than I can buy it anywhere else.
It takes a little while to get into the swing of shopping LC (probably the first month) but when you get used to it, it's a snap. Before long, you know who has the best buy on salad dressing, eggs, cheese, and so on, just as you do with the products you buy now.
And selfish? Good grief! As Lisa said, what's so selfish about trying to take care of yourself? One of the best things you could do for you and your family is to put not only yourself, but also them on a healthier way of eating. And trust me, if they don't need a LC diet, they will still benefit from yours because you'll be seeing how you benefit, and you'll be putting a whole lot healthier food on the table for everyone.
Oh yeah! Before I forget. Our suppers before starting LC consisted of 2-2.5 pounds of meat (uncooked weight), a true low-carb vegetable or two and a starchy food (rice, potatoes, pasta, biscuits, whatever). Now our supper consists of 2-2.5 pounds of meat (uncooked weight) and two low-carb veggies. Sometimes we cook extra meat to have for lunch the next day. Breakfast of eggs and berries and cream is cheaper than cereal and all the recommended goodies to go with it (toast, juice, etc.). And basically all the money we were spending on low-nutrient, high-carb foods like bread, cereal, potatoes, rice, chips, sugar, flour, etc., etc. every month is now being spent on high-nutrient vegetables, nuts, berries, a box of Splenda, and a few LC baking ingredients (and the baking ingredients are used very sparingly.