I Need A Comeback Line

We are trying to pinch pennies at our house, so there are a bunch of things we do that are different from the way the majority does them-- things like using cloth diapers, making our own clothes, and cooking from scratch instead of getting pre-made meals. I really do get a kick out of doing things myself, but I find that my ideas for cutting corners are met with something less than enthusiasm by the outside world. Inevitably I get asked stupid questions like, "Why don't you just use disposable diapers?" or "Why don't you buy X Brand Insta-SpensiFood, Now With Extra Preservatives?", as if I'd reply, "Gee, I never considered that! I must have missed the ad that was supposed to awaken my intellect to the product you advocate. Who would want to pinch pennies when such a wonderful product is available for purchase at local retailers?? I guess I'd better go out and get some right away before the DayTimer Police catch me trading any more of my valuable time for a savings in money!" It's like living in a giant commercial sometimes. Occasionally a tip like this leads to a product I really can use, but I'm a pretty good shopper and can usually find what I need without such tips. And at this point they are doing more harm than good.

I don't want to reply, "We're on a really tight budget, and by the way here's a copy of my credit report, so that you'll see just how tight it is and quit pestering me." I'd like to have an answer that will do four things:

1. be polite and unsarcastic (I have no trouble thinking of rude comebacks myself, but I'm not at my best when I'm being sarcastic)
2. be reasonably truthful (I'm not opposed to a little "spin")
   
3. not include airing my financial dirty laundry
   
4. communicate that I have no desire to be on the receiving end of further recommendations of products to buy

I've tried "Thank you" and variations on "We're not interested right now," but they don't seem to meet criterion #4. Any ideas?